Part-time hours at Home Depot

I recently took a part-time job as a Kitchen Designer at Home Depot. During my interview I was told I choose my own hours throughout the week and I'm expected to work one Saturday or Sunday each weekend. Can someone please tell me how this system of "choosing your own hours" works? Do you really choose your own hours and if so, what are the shifts like? Or do you tell the scheduling coordinator what days you can work and your hours are chosen for you? Any information regarding part-time jobs with Home Depot would be extremely helpful to me. Thank you!