BuddyPress.org

Howdy friends,
I am seeking a simple explanation which summarizes the ways in which users can be added to a private group.

Here is what I have so far:
1. By a user requesting membership by clicking the REQUEST MEMBERSHIP link on the group summary page. The request goes to the group’s administrators.
2. By a network SUPER ADMIN using the BuddyPress Group Management Plugin from the Network Dashboard at BUDDYPRESS > GROUP MANAGEMENT.

What other methods are there? How can group administrators who are not Network Super Admins add and remove members from their groups?