This is a big day for someone new to Firearms and never been to range. They are silently asking them selfs what do I wear? They don't want to ask anyone but unsure. I would like to give some pointers on this subject.
First, what is the weather that day? Hot, nice or cold? This will be your starting place. Second, one of the most important things is close toe shoes. No heels, no high heel boots, and no flip flops or sandals. There can be mud, stickers and ants.
Third, when going to range no muscle shirts, low cut shirts. The reason is hot Brass can Burn whatever it hits.
Fourth, it's recommended to wear long pants, jeans. We need to have them protected too.
Lastly, bring a baseball cap, or headwear to protect from wind, cold, heat and makes sure hair isn't in way when learning or training.