I agree with Patricia Drew and Quilter Momma. Attach the piping and then the binding. Sew as usual. Might want to add a bit to width to the binding as the quilt will now have another double layer of fabrics and I like mine snugged up. Cut mine out per normal width before I sent quilt to be quilted. Got the notion to add the flange and then oops! No more fabric, so sometimes it was a tug of war to get the binding to cover.