Pretty easy, all you need to do is cut the joint at point where the primaries start. Just cut around it and then you need to cut through some tendons and such, once it's free of the rest of the wing you will need to set it and allow some dry time. For a flydown wing I leave the feathers overlapped by half the feather follow each one. May sound odd by what I mean but you do not want separation between each feather, you want overlap. I just use some borax and you can either put weight or pin in place till it dries. Takes a couple of months to totally dry out. I have some tanned deer hide (no hair) that I cut in thin strips, wet the wrap over the bone end just to make it comfortable in hand. The last piece of hide will hold it all in place once it dries it will almost harden in place. I also cut the length down (Tip End) so it fit in my pack...
MK M GOBL