Installing an Operating System in 2025: 12 Easy and Safe Steps for Beginners

Introduction

Installing an OS sounds scary the first time, but it’s actually a simple process if you follow the right steps. In this guide, we’ll do it end to end: download the ISO, make a bootable USB, boot the PC, installing the OS, and set it up for daily use.

We’ll use Ubuntu (Linux) as the main example (free and beginner-friendly) to guide you step by step through installing the required tools. Ubuntu is widely used, stable, and well-documented, making it ideal for beginners who are setting up their environment for the first time.

I’ve also included a quick Windows reference section so you can follow the same logic if you’re installing on a different system. While some commands and tools may vary, the overall process remains very similar.

Before you begin installing, ensure your system is updated and you have a stable internet connection. Follow each step carefully, run one command at a time, and confirm the output before proceeding. Most issues during installing happen when steps are rushed or skipped.

Take your time, stay focused, and follow the instructions in order. By the end of this guide, you’ll complete installing everything successfully and have a fully working setup ready to use with confidence.

1) System Requirements

A quick checklist before you start:

Tips

Backup important data.

Note your boot menu key (F12/F10/Esc/Del).

If your PC is older, you may need Legacy/CSM. For new PCs, use UEFI + GPT.

2) Download the OS ISO File

A. Ubuntu (Example)

Go to Ubuntu’s official website and download the Desktop ISO file. It’s recommended to choose the LTS (Long Term Support) version for better stability and long-term updates.

If you’re already using Linux, you can download the ISO directly through the terminal:

wget https://releases.ubuntu.com/24.04/ubuntu-24.04-desktop-amd64.iso

This command will start downloading the Ubuntu 24.04 Desktop ISO file to your current directory.

After the download completes, you should see output similar to:

Saved: 'ubuntu-24.04-desktop-amd64.iso'

This confirms that the ISO file has been successfully downloaded and is ready for the next step, such as creating a bootable USB.

B. Windows 11 (quick)

Go to Microsoft’s official website and download the Windows ISO file directly, or use the Media Creation Tool provided on the same page. The Media Creation Tool is recommended for most users because it automatically guides you through downloading the correct version and creating a bootable USB for installing Windows safely and properly.

Before installing, always ensure you are using the official Microsoft source. This guarantees that the ISO file is authentic and optimized for installing the latest version with all security updates included.

Avoid third-party websites, as unofficial files may contain modified or unsafe versions of the operating system, which can cause serious issues during or after installing. Using the official download ensures you receive the latest updates, proper security patches, and a genuine installation file, making the entire process of installing Windows smooth and secure.

3) Create a Bootable USB

Method 1 (Windows) — Rufus (very easy)

Open Rufus.

Insert USB → Choose your ISO.

Partition scheme:

GPT (UEFI, new systems)

MBR (legacy BIOS)

Click Start → confirm format → wait till READY.

Method 2 (Linux/macOS) — dd command

Find your USB device (example: /dev/sdb). Be careful—this erases the USB.

lsblk

sudo dd if=ubuntu-24.04-desktop-amd64.iso of=/dev/sdX bs=4M status=progress oflag=sync

Replace /dev/sdX with your USB (e.g., /dev/sdb).
Output (example):

8589934592 bytes copied, 360 s, 23.8 MB/s

4) Boot from the USB

Keep the USB plugged in.

Restart PC → Press F12/F10/Esc/Del (boot menu).

Select your USB device.

You’ll see the installer screen.

Ubuntu first screen (example):

Try Ubuntu

Install Ubuntu

Choose Install Ubuntu.

5) Partition the Drive

Two options:

A. Beginner (recommended)

Erase disk and install Ubuntu → the installer will handle partitions automatically.

B. Manual Partition (custom / dual boot)

Basic safe layout (UEFI systems):

EFI System Partition: 512 MB, FAT32, mount /boot/efi

Root (/): 30–60 GB, ext4

Home (/home): remaining space, ext4 (optional but useful)

Swap: 2–8 GB (optional; can use swapfile later too)

Check disks (live session terminal):

sudo fdisk -l

Output (example):

Disk /dev/nvme0n1: 512 GB

/dev/nvme0n1p1  512M  EFI System

/dev/nvme0n1p2   60G  Linux filesystem  /

/dev/nvme0n1p3  430G  Linux filesystem  /home

/dev/nvme0n1p4    8G  Linux swap

6) Install the OS (Installer Screens)

Select Language, Keyboard, Wi-Fi (if needed).

Tick Install updates and 3rd-party software (helps drivers).

Choose Install type (Erase disk or Manual).

Set Timezone, Username, Password.

Click Install.

Installer messages you may see:

Copying files… 45%

Installing system… 78%

Installation complete.

When it says done, remove the USB and press Enter to reboot.

7) First Boot and Login

After installing Ubuntu completes, your system will reboot and display the login screen. Enter the password you created during setup to access your desktop for the first time after installing the operating system.

Once you’re logged in, open the Terminal by pressing Ctrl + Alt + T, and verify your Ubuntu version using:

lsb_release -a

This command confirms that installing Ubuntu was successful and shows details such as the release version and codename. If the displayed version matches the one you selected before installing, your system is properly set up and ready for updates and further configuration after installing.

lsb_release -a

You should see output similar to:

Distributor ID: Ubuntu
Description:    Ubuntu 24.04 LTS
Release:        24.04
Codename:       noble

This confirms that your installation was successful and you’re running the correct version. If you see the expected release details, your system is ready for updates and further configuration.

8) Post-Installation Setup (do this now)

Update + base tools

sudo apt update && sudo apt upgrade -y

sudo apt install -y curl vim net-tools git

Enable firewall

sudo ufw enable

sudo ufw status

Output: Status: active

Quick network check

ip a

ping -c 3 google.com

Media codecs (optional)

sudo apt install -y ubuntu-restricted-extras

9) Windows 11 — Mini Install Guide (For Reference)

First, create a bootable USB using Microsoft’s Media Creation Tool (recommended for beginners) or use Rufus with an official Windows 11 ISO file.

Insert the USB, restart your system, and boot from the USB drive. Once the setup screen appears, click “Install Now.”

Enter your product key if you have one, or choose “I don’t have a product key” to activate later.

Select “Custom: Install Windows only (Advanced)” when prompted. Then carefully choose your target drive or partition. If needed, delete existing partitions to perform a clean install — but remember, this will erase all data on that drive.

The setup will copy files and reboot automatically. After installation, complete the OOBE (Out-of-Box Experience) by selecting your region, creating or signing in with a Microsoft account, and adjusting privacy settings.

Once you reach the desktop, run Windows Update immediately to install the latest updates and drivers.

Dual-boot tip: Always install Windows first and Linux afterward. The Linux installer will automatically detect Windows and add it to the GRUB bootloader menu.

10) Common Errors and Quick Fixes

11) Handy Commands (You’ll Actually Use)

These are practical Linux commands you’ll use regularly after installation.

Check Disk Space

df -h

Shows disk usage in a human-readable format (GB/MB). Useful for quickly checking free storage.

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Live CPU & RAM Usage

top   # press q to quit

Displays real-time CPU and memory usage. Great for monitoring system performance and identifying heavy processes.

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List Hardware Information

lshw -short | less

Provides a summarized view of your system hardware (CPU, memory, storage, network, etc.).
Use arrow keys to scroll and press q to exit.

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Create a New Admin User

sudo adduser newuser
sudo usermod -aG sudo newuser

The first command creates a new user.
The second command adds that user to the sudo group, granting administrative privileges.

These basic commands build real confidence when managing Linux systems.

12) Conclusion

That’s the full journey: ISO → bootable USB → boot → install → first login → updates → ready to use. The entire process of installing an operating system may look technical at first, but once you complete installing it once or twice, it becomes second nature.

If you’re learning IT, mastering installing systems is a core foundational skill. Practice with different Linux distributions, experiment with manual partitions, and understand how bootloaders like GRUB work. The more hands-on experience you gain with installing and configuring systems, the faster your confidence will grow.

13) FAQs

Q1. How long does a fresh install take?
A clean installation usually takes 15–40 minutes, depending on your system. Systems with SSDs install significantly faster than those using traditional HDDs.

Q2. Can I install without losing data?
Yes, it’s possible by using manual partitioning and avoiding formatting your data partition. However, always create a full backup before starting. Even small mistakes during partitioning can lead to data loss.

Q3. GPT vs MBR — what should I use?
Use GPT with UEFI on modern systems (recommended). Choose MBR only if you’re working with older BIOS-based machines. GPT supports larger drives and is more future-proof.

Q4. Do I need internet during installation?
Internet is not mandatory for installation, but it is highly recommended. It allows the system to download updates, drivers, and security patches during setup.

Q5. Is dual-boot safe?
Yes, dual-boot is safe if done properly. Always install Windows first and then Linux. Be careful while creating partitions and keep backups before making any changes to your disk.