Manage -> Add Administrator . To add an admin they must first sign up in the Winito system. They can do this by going to your team/school site, selecting "Login" and then selecting "Sign Up"
Once they sign up you can add them as an admin by using their email or username they signed up with.
Adding them as an admin from a team page makes them an admin for just that team. Adding them from the program homepage makes them an admin of each team in the program and the program homepage.