Quilt backing?

Hi - I have been hoarding a blanket that I’m telling myself I want to use as quilt batting (for better or worse). Sure i understand sewing together the quilt front in theory, but what do you do for the back? Is it just one piece of fabric? A separate more simple quilt? I will get to how to sew them all together and how to finish the edges later…. I also ambitiously think I can hand sew this despite not knowing anything about what stitch to use. Just love hand sewing, we do have machines I just find them too much hassle. Thanks!