First, download the current version of Ubuntu Server. Currently, it's 16.04 LTS (always choose an LTS version). A 64-bit version is recommended. A 32-bit version is available though.
After downloading the ISO image, you need to create a bootable CD/DVD or USB flash. If you have already done so, put the disc in your drive, or insert the USB flash, and reboot your machine. BIOS must be set up to boot either from the CD/DVD or USB flash depending on which installation method you choose.
Follow the steps shown in the images below.
1. Select language of OS.
2. Install Ubuntu Server.
3. Select language of installation process.
4. Select your location.
5. Configure the keyboard.
6. Detect hardware - CD-ROM drives.
7. Loading additional component.
8. Detecting network hardware.
9. Attempting IPv6 autoconfiguration.
10. Configuring the network with DHCP.
11. Configure the network.
12. Set up the users and passwords.
13. Settting up the clock.
14. Configure the clock.
15. Detecting disks and all other hardware.
16. Partition Disks.
17. Installing the system.
18. Configure the package manager.
19. Configuring apt.
20. Configuring tasksel.
21. Software selection.
22. Select and install software.
23. Install the GRUB boot loader on a hard disk.
24. Finishing the installation.
25. Reboot and login on the server.
Please post your comments or suggestions.