Here’s a step by step guide on how to add somebody as admin.
First step visit your Fan Page and click on Settings on the right hand side.
The second step is to click on Page Roles on the Left Hand Side
The third step is to select ADMIN in the options.
Then write the email you wish to add as an admin:
Once you typed the email you want to add click SAVE on the right hand side. You will see a pop that will require your password (your Facebook Personal Account password)
You just added a new admin to your fan page!