It depends on the store. Some department TL's make the schedule for their workcenter, some stores have the ETL's make the schedule, some stores have HR team members do schedules for certain workcenters (usually cashier schedules.) Ask your TL, he/she should know who makes your schedule.
Hours you work are based on your availability and how many hours are allocated for each workcenter. So the person who writes the schedule gets the amount of payroll hours they can spend, and the schedule is written based on when they'll need the most staffing. If you're available when they need people, you'll probably get scheduled.