Hi Alden, 

Welcome to Box Community and glad to assist! 

To add one or more managed users manually:

1. Go to Admin Console > Users and Groups.


2. Click the Managed Users tab.


3. Click Add Users () and then click Add Users Manually.
   


4. Enter the managed user's name and email address. 


5. Optionally select Groups for the user to be a member of and Folders for the user to have access to.


6. Optionally hover over a user row and click the gear icon () to configure other user settings for that new user or click  and then click Select User Settings for All Rows to configure other user settings for all new users. See the Managed Users Tab section of Users & Groups Settings for details.


7. Optionally click Add User to add a row to the table. Then repeat steps 4 through 6 for each user.


8. Click Save.

Once you create the user, you can additionally configure the user account.

If you come across an error while adding existing users, please visit this article to fix the error. 

Hope it helps!