Their are thousands of guides on the net just google it
Code: 
http://www.usefuljaja.com/vps
<that was the 1st one on google
TO install gnome just
Code: 
sudo apt-get install gnome
And here is a useful guide for vnc
Code: 
http://lifehacker.com/317125/set-up-vnc-on-ubuntu-in-four-steps