At the end of the following points, you will have a new user in your GitLab system:
Log in as an admin user.
Go to the Admin area section.
Enter the information for the new user. For this example, I'll pick the following information; you can pick whatever you want, but the e-mail address has to be accessible to you as the activation link will be sent there. The following information needs to be given out:
Copy the password and click on Click here to login.
When you log in, you have to pick a new password and click on Set new password.