Fold down the ends of the base fabric to form points. Iron and hand tack.
Draw a line down the center of base fabric piece.
Hand stitch one edge of scarf to back of base fabric along center line as shown.
pin down and hand stitch remaining edge (stitch through into base fabric).
Fold over, iron, and hand stitch down ends of scarf into points. Stitch through into base fabric for stability.
Determine the best location for the ties by trying on the belt and safety pinning the ties in place. Experiment until you are happy with the look. Hand stitch down the ties (go all the way through all layers of fabric to back side for strength).
Done! Other advice: Press as you go for a clean sharp edge.