To grant MyPark permissions, you must already have admin rights to it.
Go to the page you want to give rights to
Click on 
Click on the Permissions Tab 
if there is no admin role there already, click on Add a Role 
Put in Admin role 
Click Add individual User to get this interface to add users click OK
And after that you can click can return to the page and set permissions for Admin
Scroll down and click Save
and permissions should be done. A few things may be skipped if the Admin role is already created.