Hi and Welcome!
Your actions as a new user are limited for the moment. (General spam protection)
Reading through topics and commenting on other posts gives you relatively quickly access to all necessary features.
The Create topic button is under your profile on the right side for when you can see it.
In the meantime feel free to ask anything in your Questions thread
or chat in our Public chat room
I’m excited to have a member of the AdobeXD team on the forum! 