keeping going until you only have one stitch left on your needles. then cut the yarn about 5 inches. Take that 'tail' and pass it thru the middle of the one remaining stitch and pull it all the way thru and pull it tight until the stitch tightens around the tail. Pull it enough to snug up the knot. Now you can weave the tail thru the stitches on the back. cut it off close to the fabric.