My recent experience using Open Atrium for Google Code-In

Hello!
I'm supposed to do a task at Google Code-In 2013 in which
I should install and configure Open Atrium site. I used
getpantheon.com services and the installation was quite
fast. Open Atrium has a lot of functions and modules and
I'm sure that I'll use it in my next projects. I hope I
will successful achive the task.
Was easy to:
1) install Open Atrium
2) start a discussion
3) make a screencast
Was confusing to:
1) set the people permissions( I'm not sure I was supposed
to enable the register for users or to change permissions
being sure that anyone can post comments)
It would be easier:
1) if when we start a discussion thread we can set post
comments permissions only for that thread