Need some advice

Hi! I’m trying to improve darkening and texture on my inner thighs and armpits. I have sensitive, somewhat dry skin.

I’m planning to use glycolic acid but I’m not sure how to build a simple routine.

Can I use it on both areas? How often should I use it, and do I need to moisturize after? Also, do I need sunscreen if those areas are usually covered?

I’m looking for something simple and not too harsh because my skin gets irritated easily.