Hi Ruth

As an admin on a group you have access to the "Managing your space" area which might help answer some of your questions.   You can get to this by rolling over the "My Group spaces" in the top navigation bar and the list should appear.

To leave a group you should see an "Unenrol me from groupname" option in the right hand column when you are on the group.  

To request a new group you need to contact us to request.  I assume you were added as an admin by a colleague or it was several years ago as we would have sent you info on requesting help.

Group spaces can be set to be open to any without login, or restricted or partial - it depends what you want to do in the group.  This is something we clarify when you request the group.

I will be in touch by direct email shortly.

Lorna Renton