I've always done delivery but did in-store pickup for the first time this year so sorry if this is a stupid question. My confirmation email says: Ready for Pickup on Sep 16 Check-in Window: 8:00 a.m. - 8:30 a.m. Does this mean I have to be at the store at 8am or else I miss it? Or is this something I do online and then I can go to the store later? Thanks for any help.