What do the different roles within group mean?

Group owner:

• Can invite users, manage users, remove users
• Can create logins, edit all logins, delete logins
• Can move logins from one group to another group
• Can transfer the ownership of a group
• Can delete the group

Group admin:

• Can invite users, manage users, remove users
• Can create logins, edit all logins, delete logins

Group user:

• Can create logins
• Can edit logins if created by them