Make A Pot Rack How Do I Mount A Pot Rack To Drywall?

How do I mount a pot rack to drywall? - make a pot rack

I live in an apartment and trying to make a pot rack in the plasterboard wall. I've found a stud finder to get the studs (16 inch). Then I drilled pilot holes and used # 12 2 1 / 2 "wood screws to mount the pot holder. Two screws broke when I was screwed on - one with an electric drill, a hand. Am I missing something or hurt ? I have very little experience with renovations. Thanks!