To create a Group, click on Groups in the left navigation bar. Next, click on the + button in the upper-right corner of the panel and select Create Group.
Give the Group a name, then choose whether the group will be Private or Public.
Private groups are groups that do not appear in the Groups list for users to join. A user will need to be added to the group by an existing group member in order to see the content.
Public groups are groups that appear in the Groups list. By clicking on the Group, any user will be able to freely join the Group.
Next, choose what role new Group members will be given. If you select Viewers, they will only be able to view existing content. Selecting Contributors will allow users to upload new content as well. The role can be changed on a per-user basis once they are in the Group.
Last, simply choose whether or not you want to allow users to create questions in a style similar to Quora. If enabled, you can also require questions to first be approved before they are made visible in the Group.
Once done, just click Create Group!