To add other leaders to a community:
Open the Pray app and tap the pray icon at the bottom left (if you are in another community, you'll need to switch to the one you would like to manage)
Tap "Team" below the banner image
Type the name on the "Find a member" box
Once you've found the member, tap the 3 vertical dots at the right and select "Edit Member Settings"
Tap the button at the right side of "Leader" and make sure it turns blue
Tap "Done" at the top right
You have successfully added a leader to your community.