Step 1: Accept Friend Request
Keep in mind that if you're not friends with the person you're giving access to, they'll have to accept your invite before they can start helping you manage your Page. Your Local Marketing Account Manager will take the first step and request you as a friend, so be sure to keep an eye out for their friend request.
Step 2: Give Someone a Role
If you're an admin:
Click Settings at the top of your Page.
Click Page Roles in the left column.
Type a name or email in the box and select the person from the list that appears (e.g. firstname.lastname@example.org).
Click Editor to select a role from the dropdown menu.
Click Add and enter your password to confirm.