Just lay the border on the top with right sides together, then sew as if you were putting binding on then press the seam towards the border once it is sewn on. Once you have the border on you can finish quilting it any way you like to match the rest of the quilting. I don't think you have to hand sew it though I would do it by machine. It would be kinda like a quilt as you go border. You would end up seeing the "quilted" seam on the back of the quilt but the seam allowance and everything would be hidden inside. Does that make sense?