Once you’ve chosen the right prepackaged leader (click here to see a video on how to do that), then you have to get it out of the package and onto your fly line. That first step sounds deceptively easy, though, and many anglers manage to create tangles or knots in the process. In this video, Dave Lovell of Trouts Fly Fishing in Denver, Colorado, shows us a simple trick to unravel the leader cleany, with no tangles.
This is the way I do it, but with one change. I find it easier to undo the butt-section wraps before I put the coils over my fingers. Tomayto, tomahto.

I didn’t hear him mention that you better make sure the butt section is completely unwound from the rest of the leader before you start pulling it off your fingers.
You unwrap it from your fingers while spreading them to keep tension on the coil, as opposed to pulling it off the tips of your fingers. Pulling it off like that is what causes the tangles. He clearly shows and describes puttingtension on the coil, unwrapping the butt end from around the coil, then unwinding the leader from around your spread fingers.