You can get to your Communities profile information by clicking on your user avatar at the top-right of the site.
Choose "Profile", then click "Edit Profile". Take the time to populate and/or update it with your avatar, screen name, biography, education, work history, and certifications -- this helps identify your background, experience, and interests.
Note that the Communities "Profile" is currently independent of the Bentley User Profile. This is to accommodate information that is exclusive to Bentley Communities.