At my gym, we all warmed up and stretched. Then we did tumbling. And last we did some stunts. I know most gyms make you learn a little dance at the end too. My tryout process was one day only, for an hour and a half but every gym is different. Wear something comfortable, like what you would wear to workout (shorts and a t-shirt). Put your hair up in a high pony or have it pulled back at least. My gym doesn't require any make up, I usually do light foundation and mascara but it depends on the gym. Don't wear make up if you don't feel comfortable, unless the gym has specifically stated that they want you to look a certain way. You usually won't find out your placement till anywhere from a day to weeks later depending on how big the gym is and how many people tryout. I found out a week after I tried out. Unfortunately every gyms tryout process is different but hopefully this helps a little bit!
Edit: Ultimately just have fun!! Everyone's a little nervous for tryouts but just smile and do your best :)