How to Assign Administrator Roles to a User

From the Admin console dashboard, go to Users.
Click a user's name to open their account page.
Scroll to the bottom and click Admin roles and privileges.

Tip: To see the privileges granted by the user's current roles, click on the panel to expand it.
Click Assign roles.
Choose a role from the Roles list.
(Optional) If the role includes user management permissions for organization units, select them from the No Organizations selected list beneath each role. Click Save.
Click Manage Roles to assign more roles to the user.

Alternatively, you can also manage all your admin users via Accounts > Admin Roles. You can make different users admins with limited access to different services for easy management.