1st day you wont be rolling... so no need to worry bout that.
if your schools anything like mine... you'll start with jogging. then skipping, jumping touching the floor and other stuff while jogging.. after that, you'll line up and do stuff thats hard to explain by typing.. stuff like falling backwards, then kicking your leg out and standing up again, and sprawls.
then more than likely you'll get a water break, come back in 2 minutes, and your instructor will teach everybody a technique then everybody will practice it on each other.
after that he'll teach everybody some more things and with about 20 minutes left in class, your gonna watch 3 5minute rounds of fellow students rolling with each other