Here are the detailed instructions:
Begin by wrapping thread on the hook shank from 1/2 inch behind eye to start of bend. Attach tag end of ribbing along bottom of shank, with ribbing extending behind fly. Cut a 6" piece of each color of yarn and separate one strand of each color. The yarn is 4 ply, but I used only one strand of each color. Use more if you want a thicker body. Attach the tag ends of the yarn along the bottom of the shank, with the rest of the yarn extending behind the fly. The tied down body and ribbing should cover only the pre-wrapped section of the shank, leaving about 1/2" of bare shank behind the eye. Wind the green strand of yarn forward to where the bare shank begins, double back a few wraps, then wrap forward again to form a tapered body. Tie down the loose end. Now wrap the yellow piece forward, covering the green yarn, and tie down the loose end. The green yarn will show through the yellow layer when the fly gets wet. Note: This yarn will pull apart if you apply too much tension. In order to get a tight wrap, apply light tension on the loose end and gently twist the yarn on the shank with your other hand as you wrap the shank. I think the original fly used yellow dubbing over green dubbing to form the body, so you could certainly use that method rather than using the yarn.
Now tie in a piece of red tying thread or floss where the body meets the bare shank. Wrap the thread or floss back and then forward to cover about 3/8" of the body, then tie off. The length of bare hook will "shrink" as you tie down the ends of the body sections. You should still have 1/4" - 3/8" of bare shank behind the eye, with about a 1/4" tapered section of thread between the bare shank and the body section.
Take two matching olive grizzly hackles, approximately 2x the hook length, and tie them "Matuka" style to form the wing and tail, using the wire ribbing to hold down the hackles. I've found that it's easier to lash the hackles in place if I make one wrap with the wire before I begin to secure the hackle. The bases of the hackles and end of the wire should be tied down where the tapered section of thread is so that the wing begins at the front of the red floss.
Take two or four short curved grizzly feathers and tie them on the sides of the fly to make fins (I used two, the original used four). Again, tie the bases of the feathers onto the tapered section of thread. The fins should be almost as long as the body and should flare out from the sides of the fly. I'm not sure what kind of feathers were used on the original fly, but I didn't have anything like them so I used the small hackles that were attached to the bases of the wing hackles and trimmed the tips to form a blunt fin. Tie in the throat if desired (the original didn't have one).
At this point you should still have about 1/8" - 1/4" of bare shank just behind the hook eye. Tie in two or three bunches of olive or natural deer hair to form a muddler style head (original used natural). I try to tie the first bunch on the tapered section of thread (it doesn't always stay there) and pull the thread tight without spinning the hair. Then spin/pack a couple more bunches up to the eye of the hook, tie off and cement thread. I also applied a small dab of head cement right at the base of the tail to help keep the wing/tail in place. Trim the hair very short on the bottom and leave the tips from the first bunch on the top and sides to form a collar. Trim the rest of the hair to make a tapered head.