I just signed up for professional, but I still can't access the add on downloads. I need to read how these work too. I am assuming that is what the "project" button is, but that doesn't go anywhere either.
You should have a Doc-Subs tab in your profile that gives you direct links to all your CB Team addons and you should be able to access the incubator project area also here:
forge.joomlapolis.com/projects/incubator?jump=welcome
If you are still having problems, please send me a private message and I will assist you personally.
nant