Assemble the wing before you start: pair the four grizzly hackle tips into a single unit with a jungle cock nail on each side, tips aligned.
Start black thread well back from the eye (this fly carries a lot of material at the head, so leave yourself room) and wrap a thread base back to the 15% point.
Tie in the Mylar tinsel, silver side out, wind the thread back over it then forward again in slow touching turns keeping the tinsel on top of the shank.
Wind the tinsel forward in touching turns to the thread, letting no black show through; tie off and trim.
Stack a sparse bunch of white bucktail, measure it about one hook-length (or slightly longer, your choice) and tie it in on top as the underwing. Keep it sparse and use straight fibres.
Tie in five or six peacock herls over the bucktail, the same length as the bucktail, taping the tips together beforehand keeps them from shifting, and bind them down.
Turn the fly and tie the orange saddle hackle fibres in underneath as a throat with a loose wrap first so you can centre them, then lock them in. Leave the thread at the back of the head area.
Set the pre-assembled grizzly wing on top and tie it in with a series of loose wrap-and-pull turns so it sits on top of the shank and does not twist over.