Welcome to both Guisureth and Gherwina - it's good to see two more Goths here, and one of them a Gunthigg.

To answer your question Guisureth - if you go to the group's front page and look at the list of members on the left hand side of the page, you'll see a link at the bottom of that list saying "Join this group". If you click on it, you will go to the joining page. Joining a group costs a small amount of sesterces. Novices can join only one group, though Citizens and Patrons can join more.

I hope that helps,
Thiu