These are the steps I took in setting up Linux Ubuntu Server 14.04 LTS on my spare computer.
Download Ubuntu Server from the official site
Make a bootable USB stick following this guide
Insert new bootable USB into what will be your server, then turn it on
Follow the installation instructions
Firstly you’ll need to select a language. I picked English - my native tongue.
The next step will give you a number of options:
Install Ubuntu Server
Multiple server install with MAAS
Check disk for defects
Boot from first hard disk
Rescue a broken system
I first selected ‘Check disc for defects’. Once that had run it restarted the install process. I then selected ‘Test Memory’ and let it do its thing. I’m not quite sure what I was looking for with these first couple of tests. I’m no system administrator, so anything short of a red flashing light would look fine to me.