Remember, there are a few steps:
1: Become a Member (Free)
2: Subscribe for either or both:
a: MITB Sports Flex League Tennis
b: MITB Sports Team Tennis (Captains First)
For Team Tennis, once you have the subscription a captain will register their team and get a Team Number that the captain will give to the players to register themselves on the team.
Already a member and already paid for your subscriptions? Go to your “My Account” page and at the bottom, Register and Play.