Follow these steps to add a new user account:

1. Click the Apple icon at the top left of your screen, then select System Preferences.
   
   The 'System Preferences' window appears.
2. Double-click the Accounts or Users & Groups icon.
   
   The 'Accounts' window appears.
3. Click the lock icon in the lower-left of the window, then enter the administrator username and password.
4. On the lower-left of the window, click the + (plus) button.
5. Complete the fields on the page, then click the Create Account button.

To log in to the new account, reboot the Mac and select the new user profile.