This is one of the first projects I have my sewing club students make as rosettes are super simple and you can do about a zillion things with them. They are also really hard to screw up and a great way to practice stitching by hand if you’ve never done it before.
Knot one end tightly. You will be twisting the band of fabric as you roll it around the knot in a spiral. There is no right or wrong way to sew this up, just make sure everything is secured and that you keep the stitches on the back side. Make sure to finish off your stitches by sewing three or four stitches on the same spot.