Hello,
there are many amateur leagues, but I don't know how can you contact a team. If you're a student is easier as many schools and colleges have a team. I think the easiest way to play football is to make a team (5) to play indoor, and you can join any league in any polideportivo.
If you play really good it could be easier to join a team (11), in september they will beguin training, if you see a court in your neighbourghood, probably a team will train there, try to join them.
Good luck.