Welcome Mabel!
I think you'll get the hang of this, though it's a bit confusing at first!
I'm not sure if you can even tag or @mention folks on a bbs? It's be awesome if you could! Maybe a real old hand can show us?
Anyhow, I find the most useful button to be the "You have # unread posts." in the upper right under "log out". Click that and it'll show you most new activity since you're last visit. In settings you can filter it to dis-include forums you don't want to show up (Mature for me since I can't stand to see politics talk when I'm emotional open/vulnerable).
Your profile also shows you the activity of your friends which is nice.
Blogs are like their own thing, and get *some* use, so you can check em out periodically. I guess it's like a way to have a more selfish thread? I dunno...
Groups sound great, but have very little activity as far as I can tell, mostly I bet because it's hard to see update... I should start an EC thread about that actually.
Anyhow, hope that helps!
Why don't you tell us a bit about yourself outside of your interest in ABDL stuff? Lots of folks make friends here because of their common interests outside of this ... stuff.