The communities that you already belong to are listed in the left pane.
To find more communities:
Select Discover Communities.
Browse or use Search to find communities.
Check out the About page, scroll through the community feed, or look at members to find relevant communities.
Select Join when you find a community you’d like to join.
Under Community Members, enter the names or email addresses of anyone you want to add to the community.
If it’s public, you’ll be added right away. If it’s private, you’ll be added if the community admin approves your request.