Lay a black thread base all the way back to the bend, then cord the thread up and build a small bump right at the bend - that bump is what splays the biot tail.
Pick two brown goose biots matched to the hook size (middle of the quill for a #10), grab them by the tips and snip them off, then flip one so the pair curves away from each other with the tips aligned.
Flatten the thread back out, lay one biot on each side of the shank with a couple of loose wraps, check the length and the splay, then lock them in with several wraps working back. Bury the butts or snip them off.
Catch in the remaining components in the reverse of the order you will wrap them: the small copper wire rib first, then the brown rooster hackle, and the peacock herl last.
Bind the hackle in from the thick side and spin it so the barbs will stand perpendicular when you start wrapping; bind the stem forward and trim it, since the peacock herl body will bury the step.
Take the thread back and catch in three peacock herls (four or five is fine on a long body), leaving the thread hanging about mid-shank so it can hold the herl if it spreads. Wrap the herl forward in closely spaced turns and stop about one eye-length behind the eye, then secure with two thread wraps and snip the excess.
Palmer the brown rooster hackle forward over the herl in evenly spaced turns, keeping the barbs perpendicular to the body. You can put the turns close together because the hackle is going to be trimmed. Secure at the front and snip the excess.
Spiral the copper wire forward, zigzagging it through the barbs so you trap as few as possible. This is what locks in both the hackle and the herl. Take two or three tight securing wraps at the front, one forward and a couple back, put tension on the thread and helicopter the wire off.
Sweep any trapped barbs back, clean up and build a good big nymph head, then whip finish with four or five turns.
Trim the palmered hackle at an angle all the way around so the fly finishes as a teardrop or bullet - shorter at the rear, longer at the front. This is the slowest step, so take your time. Finish with a big drop of head cement or hard gloss.