Don't know how to install an operating system (Ubuntu)

First of all, you need a CD/DVD or a removable USB device which contains the installation files of the operating system. If you don't have any of those you will have to download the installation files from the official website and burn them to a CD/DVD or make a bootable removable USB device.

If you don't know how to burn a CD/DVD or make a bootable USB device, check out the don't know how to make a bootable (burn) CD/USB solutions.

Once you have a CD/DVD or a bootable USB follow the steps below:

1. Set the CD/DVD drive (or a removable disk) as a FIRST BOOT DEVICE in BIOS so that your computer can recognise the CD/ DVD or the removable disk which contains the operating-system install files.
   
   
   • Turn on/Restart your computer and once the logo appears, immediately press the Del(ete) key (or F1, F2, F12 Esc, or press Fn + F1/F2/F12 on some laptops).
     
     *If you were unable to access it, just restart your computer and try again, and this time read the line in the lower part of the screen to learn the combination.
     
     
   • Once your are in BIOS, use the arrow keys to navigate to Boot (or to Advanced BIOS features on some BIOSes)
     
     
     
     
     
   • Navigate to Boot Device Priority (or to First boot device on some BIOSes)
     
     

     
     
     

   • Select CD/DVD-ROM (or USB) by pressing Enter and move it upwards using the arrow keys to set it as the first boot device (on some BIOSes navigate to First Boot Device and then make the selection)
     
     
     
     
   • Press F10 to save the changes and exit BIOS
     
     
2. Insert the disk or USB that contains the Ubuntu installation files and restart your computer
   
   
3. The installation screen will appear after a few minutes -> Click on the Install Ubuntu (or other version's name) button
   
   

   
   
   

4. Select a language -> Click Continue
   
   

   

5. Connect your computer to the Internet -> Click Continue
   
   

   
   
   

6. Select whether you want to Erase the disk and install Ubuntu or Something else to create a new one
   
   

   

   
   * If you chose to create a new partition, select Something else -> Install Now -> New Partition Table... -> Click the + sign -> Select the size -> Under Use as: select swap area -> Select OK
   
   

   

   

   

   
   
   

7. Follow the instructions that will follow and after you complete everything -> Restart the computer
   
   
   
   

8. After that, wait for the process to finish. 
   
   
9. Restart your computer and access BIOS to set the Hard Disk as a first boot device
   
   

Note: Don't interrupt the process and be near the computer in case if something unexpected happens. Don't be alarmed if the computer restarts because that is a part of the process. 

If you use a laptop connect it to the AC adapter to prevent it from shutting down.