They pic two men (or male teens) for suits of armor. Someone for the Beast (the best part since that child gets to dance with Belle and wear a cape. And yes, it can be a girl who is chosen.) They pick a Maurice, Phillpe (the horse), Mrs. Potts and Chip, the wardrobe and then they have extra dishes for any child who wants a part and wasn't chosen. The ones chosen play a pretty short part (nothing hard or lengthy) My 2 year old is often picked as Chip. The parts aside from Beast just hold a large laminated picture of the part they're playing and there are a couple of CMs inside to wrangle kids and help with the parts. Then at the end any child can get in line to get a quick picture with Belle. She will not sign autographs. You get a pre-signed bookmark and the pics are taken by a Photopass photographer. The light in low in there and you cannot use a flash for personal photos. A good deal of the attraction is in Maurice's workshop before you go see the magic mirror and then in front of the wardrobe being assigned the parts for the play.
It's a bit of a long attraction and one you may not want to run to first thing since you can 'waste' your rope drop advantage. Though the FP+ do go fast and the attraction usually averages an hour wait all day.