This is how I do it.
A quilt sleeve is generally 4" tall by the width of the quilt, minus an inch or two. So, if your quilt is 60" wide, you will want the sleeve to be about 58" long. Cut your sleeve fabric 8.5" tall by 59" long. Turn under the short ends 1/4" twice and stitch, so you have no raw edges. Fold the WRONG sides together, lay on top of the back side of your quilt, aligning the raw edges, and stitch 1/4" from the edge. (This will only work if you have NOT attached your binding yet. If you've already attached your binding, you'll have to sew both the top and bottom of the sleeve on by hand.) Then hand-stitch the bottom of the sleeve onto the quilt, being careful to only sew through the backing and batting, and not through to the top of the quilt. You will want to leave a little bit of space for a dowel or whatever you use to hang the quilt with, so don't sew the bottom of the sleeve flat - scoot it up about an inch or so towards the top of the quilt.
I'm sure if you google "how to make a quilt sleeve" you will probably find illustrated instructions or a video on YouTube. That would probably help a lot.