No worries, georgie -- just ask any time (you can bet if you have a questions, someone else does, too :).
To add a contact, just click on the person's username, and when you're on their profile page, have a look on the right side of the page under their userpic and you'll see a link labelled "add as contact". When you click on that link, it takes you to a page where you can write a little message, and submit. The person then gets notified and when they accept they'll automatically appear in your contacts list. Have a go by clicking on my name and see if you can get it to work
Similar thing for groups. Just go to the group home page (by clicking on a name link in a list when you see it), then join the group. Once you've joined it will automatically appear in your groups list (My Groups). Try it out with the Getting Started Group and see if that works.
Hope that helps
Di