For whatever it's worth, this is how I do it.
This is what I use.

Ensure that the nock holder on the fletching jig is horizontal. Refer to the manufacturer's instructions to learn about all the necessary adjustments that will ensure that the base of the quill rests on the shaft without any gaps.

Place the arrow into the fletching jig as per manufacturer's instructions. If the arrow nock has an index marker, this should be aligned with the cock feather.

First, place the cock feather in the clamp, with the rear of the feather aligned with a certain mark on the clamp. Some clamps come pre-marked. Mine did not. This ensures that the feathers aren't stuck to the shaft at random distances from the valley of the nock. I leave 1 1/4" from the rear of the feather to the valley of the nock. Some people leave less distance and others a little more.

Now stick the double sided fletching tape on the quill with a little overhang on either end and cut the tape. Run your finger down the tape on the quill to ensure that it has stuck evenly and there are no air gaps.

Remove the reddish protective strip from the double sided fletching tape. I prefer to use a scalpel or a thin bladed pocket knife.

Place the clamp into the jig, apply a little pressure, remove clamp, run a finger nail down the side of the quill to ensure it's stuck evenly, press and stick the tape overhangs to the shaft and you now have a feather stuck to the shaft.
