Squats with barbell question
 

I'm starting NROLFW next week. I decided next week as I wanted to start on a Monday- Wednesday-Friday schedule.

Anyways tomorrow I'm going to the gym to see what my limits are going to be so I can get an accurate amount of weight to start with. Problem is my gym doesn't have a squat rack. Will I get the same benefit of doing a squat with a bar in front of me, or does it need to be on my shoulders/back? If it does, how can I modify this?