You could use an embroidery hoop to hold the canvas to the sweater, but I was worried that it would stretch the fabric. Cut a length of DMC floss. No need to separate the length into fewer strands ...

Repeat all the way round the hoop and tie off. Don’t forget to remove your template by running a warm hairdryer over the top of your embroidery. Invest in good quality embroidery floss –DMC ...