When I go into library, there is a button that says groups. I am confused as to how it works/is used, and was hoping someone could clear it up.
Cheers!

In the library screen click the Groups button and click Add. Put a name for the new group. Then you will be able to make add files and directories/subdirectories from your library to the new group. If those files and directories/subdirectories are not added to the Public group, then they will only be visible to the groups you have added them. After you have added a group in the aforementioned way, you right-click a username and choose the group in the Groups submenu. This submenu will only display if you have set up at least one group other than the default Public group. Only the users added to the group will be able to see the files/directories/subdirectories that are visible to that group.