After you've upgraded your account to a group account, you become both the group owner and a group administrator. 

As the group owner, some of the things you can do include:
-Create new subusers
-Set permissions for users 
-Allocate different amounts of your own storage and download bytes to subusers
-Logon as any user in the group account
-View backup tasks of all group members

Subusers can take on the following user types:

Group Administrator: A group administrator has all the abilities that a group owner has, except he/she cannot modify subscriptions nor modify group account owner settings.
Subgroup Administrator:A subgroup administrator is similar to a group administrator but can only manage subusers that they created or added.
Group Member: Group members have the same abilities found with an individual account, except they may or may not be able to order subscriptions, depending on the group administrator's settings.
Guest: A group guest user cannot see any group account information, except for folders shared to him/her.