To add a new user to your employer, your designated Admin User should be able to do the below:
Click Admin, then click Employer Access Maintenance.
Enter Modify mode (Ctrl+M), then Zoom (press F5) in the Operator field.
Move down to the bottom section of the screen, then add a new line (press F4).
Press F5 to select the employer, then move back to Query mode by pressing Ctrl+Q.
Click Save.