Futsal formations

Our team has not played Futsal before. The local league allows 4 field players and a keeper on the floor. I read that it is best to use a 3-1 formation. If both teams are doing that then excess players are on defense.

Would it be better to start with a 1-2-1 and play whereever the other team allows on their side and man marking on our side.

I welcome your comments to help teach me more concerning this game.

Do you sub one or two players at a time? Subs are on the fly in this league.

Are half court shots difficult with a Futsal ball?

Any suggestion you feel a novice team should know would be helpful.

Thanks.