Video: How to Set Up a Fly Reel
If you're doing this for the first time, you'll need the following items: (1) your trout reel, (2) a spool of "backing" (for trout, 20 lb. test is typically plenty), (3) a fly line, (4) some 20 lb. monofilament (I use Amnesia, which is red), and (5) a tapered leader.
The first video demonstrates the Double Surgeon's Loop, and shows how to quickly and simply mount backing onto a fly reel spool. I have never seen anyone else use this method, so it might be new to you.
The second video shows arguably the hardest knot, the Nail Knot, which is used to connect backing to fly line. When you've watched the whole video, you might want to go back and cut your backing a foot or so from the fly line and re-tie loop-to-loop knots here, to make your fly line easily interchangeable. If you do, make sure the backing loop is at least six inches long, so you can pass it over any reel.
The third video demonstrates how to tie a nail knot using monofilament (in this case 20 lb. red Amnesia) to the front end of the fly line. This can be a critical skill to learn, because you never know when you're going to need to perform some emergency "surgery" on the water. While you can use this method to tie a tapered leader directly to the line, I prefer the loop to loop knots as demonstrated for ease of use later.
The fourth video shows maybe my favorite knot in this whole system, the Perfection Loop. While there are other ways to make a loop in the leader, the Perfection Loop is the smallest and strongest loop knot I'm aware of.
The fifth and final video will show you how to correctly mount your leader to the Perfection Loop (or to a factory loop). This one's important, folks, and probably the one I see done incorrectly the most often. Mount your Loop-to-Loop Knot the wrong way, and your casts will flop sideways and you will spook more trout than you fool.