As an administrator, you can manage users on your subscription by visiting the Manage Users tab in the Options panel.
In the tab you'll see a list of all the members on your subscription. You can easily add an additional member by clicking the "Add User" button and filling out the information of the new member.
You can also edit existing members by clicking on the pencil icon next to a member.
In Edit Member pages, you'll be able to change member details, assign subscription/channel rights, reset member passwords, transfer channels, impersonate the members, or remove them from the subscription.