What should i expect to see at a fitness center?

I’m going for the first time tomorrow with my uncle and…..

I’m just wondering about the people, workouts , etc. I’ve been working out for the past month and have been waiting to go to an actual gym and try it out. So what should i expect to see at a fitness center?

What to wear to an interview at a fitness center?

I have an interview on Friday and I really want this job.
Should I dress business or more casual since it is a fitness center?

What are the requirements for being a fitness instructor?

I would like to be a fitness teacher. One that teaches classes at a fitness center, & not a personal trainer. But I wasnt sure if certifications were mandatiory.