Intramural Flag Football/Soccer

Hi, I am a spring admit grad student and wondering how intramural works and if I can join just random team or if I need friends. I started watching/playing football with my friends this year and maybe thinking I could play for fun in USC as well. How competitive is it and how much skill do you require?(yes I am planning to join whateve the easiest). Also, I am thinking about soccer too since I did 3 years of soccer for IM in my undergrad but I would rather try something new. I am not super athletic or anything but I go to gym regularly and I think i am somewhat fit and not too slow. If you are looking for a player or anything, please hmu!