Giving other members admin status is a great way to help share the Planning of workouts for your members. Start by heading to your Admin Console by going to your gyms profile drop down.
From here select "Members" on the left hand side of the page followed by "Manage". From here you will be able to manage you members. Search for the members name and give them the admin role.
Additional admins will have all of the gym subscription holder's capabilities, including the ability to create workouts and Plan them as WODs for your members. They will not have the ability to manage the gyms subscription.