How to Add an Facebook Admin to your Page

This is the standard way of adding an admin to your Facebook page. Go to Settings at the top of your page and click on "Settings":

Then select "Page Roles" on the left sidebar:

Once there, add the email address of the person you'd like to made admin - the email address has to be the email address they use on Facebook. You also have to select their level of access your page:

Now our part is done. The person that you just made Admin should get an email from Facebook that looks like this:

This person that just has to hit on "confirm" and voila! Your new admin is added to your page.