For a knit on boarder of a shawl - starting pattern here: https://stitch-maps.com/patterns/display/starting-center-tip-for-6-yo-sawtooth-edging/
Adjustments -
Rows 66-71: Do not M1L - those are the lives stitches of the shawl that you are knitting the edging onto
Row 72: Do not CO sts, rather begin working the live stitches from the top boarder
Row 128: BO 2sts, BO2tog, incL, k1, yo, k2.
Row 129: BO 2sts, BO2tog, incL, k1.
Shown with a cast-on count of 16 stitches.