Be on one of the maths computers.

In your file manager go to the directory with your username as the title (clarkeph for me).
Create a folder called 'www' (without quotes!).
In that folder create a file: right click, click 'Create Document', click 'Empty File', enter 'index.html' for the name.
Open index.html in gedit (say) and type 'Hello world' in it (with the quotes, live a little!). Save and close it.
Right click on index.html and click properties, at the bottom.
Go to the Permissions tab.
It should say:
	Owner: Your name etc
	Access: Read & Write
	Group: maths2
	Access: None
	Others: None
Change those 'none's to 'Read only'
Go to www.maths.tcd.ie/~youruser (so, www.maths.tcd.ie/~clarkeph for me).
Google "How to take over the world using html"