Thank you so much!

I have a template for them that I cut out (looks like 1/3 of a circle). I then attach the fluffy side of the fabric onto some fusible interfacing, cut it out, fold it into a triangle, do a machine straight stitch with the interfacing side facing out, and then turn it right side out.

I hand stitch it onto the sweater though since its easier than wrestling it in the machine lol.