Groups a great social tool to allow conversation and documents to be kept and shared outside of a course. Joining a group is very simple too!
Click on the Group button in the navigation bar.
Once you are there you can scroll through what groups are public in your academy, or you can search for a specific one by its name.
Click on the name, and then you will be taken to the group page where you can click the green Join Now (underlined in blue here) in top right corner of the group page.
Some groups require approval before you can fully join, but once you are approved then you have full access to the discussions and content of the group!