Glad to have you! We have new shooters every match, so you likely won't be the only one.
The division you shoot is based in your gun or capacity, but it's the least important aspect of the match.
The important things are covered in a new shooter orientation given before the match starts. Three biggies are:
1) its a cold range; guns are empty and holstered
2) Don't draw or handle your gun until told to so
3) keep the muzzle pointed at the backstop
4) unless shooting, finger is off the trigger
Don't worry about shooting first (you won't) or from concealment.
Be ready to have some fun!