First year playing football! Don't know what I'm doing!?

Im 14 and next year I will be going into highschool. I really want to play football but I've never played before. I don't know all the positions, I don't know tha calls or plays or anything. And to make it worse my highschool has football workouts/practices almost everyday in the summer by I've already missed a month of those because I'm visiting family in a different state. Please help. I don't know what I'm doing and I don't want to look stupid in front of the players and coach.