As administrator you can manage all users. The procedure is almost identical to the user management in the author backend, with granting all rights basically for you as administrator.
On the left side of the overview you find a filter. with which you can configure the overview table on the right side. This table shows the user name, last name, first name, OE, user type and the date of creation or change.
How to create, import or merge users, see for further informations in the author backend:
Create a new user.
Merge two users.