Help? Please

scottbrianna19

So I'm new to this always had the app but never really used it until I decided to join the gym and the fitness trainer told me to actually start using it. Solar it's been pretty helpful. So question How do you join challenges? Everytime I try to join one on the challenges screen there's nothing there not even a bottom to add a challenge. And what are some of the other great things about this app that I should know about