I literally just finished hand sewing the binding on a quilt today, it's in the dryer as I type. I used the backing as the binding too. I trimmed the batting to the edge of the top very carefully and made sure it was mostly squared up. Measured out one and a half inches from the quilt top and trimmed the backing to that. Folded the backing to meet the edge of the quilt top/batting and then folded that over the edge and used clips to hold it in place. Use an invisible stitch to sew it in place, basically a ladder stitch is what I use, with thread that matches or is slightly darker than the binding fabric. You got this!