How do I add a user with full administrative rights?

I attempted to add a user with admin capabilities, however I was unable to find the page where to select the option granting them admin designation. How does one go about adding an admin user?

Answer

Go to the user page Global Settings > Users and click on the specific user. Once the individual user page is open, click on the tab labeled "Security Roles' and select the option at the top for "Admin'