Cut a minkie strip around 3 times the length of the hookshank (Can be shorter if you wish). Roughly measure a distance the length of the mylar body and part the fur. Now wind the wire around the hookshank catching in the minkie fur, 2 turns will be enough. Now stroke the fur backwards so the wire is covered.
Now take the hook out of the vice and insert it back in upside down or if you have a rotary vice, rotate the fly and then take a bunch of Hot Orange Cock Hackle Fibres and tie them in as an underwing. The length of the fibres should be roughly the same length of the mylar body.