Not really much anyone can show in a video- the one I recall seeing once ws on a Chris Helm tape, but almost all videos I've seen with harirwings use a stacker. You can use essentially anything that has a flat bottom to stack hair, it doesn't have to be a commercial stacker- I use an empty .22 casing for small amounts of hair and used to use a clear plastic pill bottle in the 'old days'.
Hand stacking is a sort of tedious process, but you can make it a bit easier on yourself by doing a couple of things. First, make sure you're starting with CLEAN hair- if you need to wash it, use something like Dawn dish detergent in warm water, because it removes a lot of oil/grease. Next, use a comb to remove as much underfur as you can while it's still on the skin. Then apply a SMALL amount of hair conditioner (yep, the type humans use) and use the comb to distribute it well through the hair, then rinse it clean and let it air dry on a stack of paper towels.
One trick to hand stacking hair is to pull the hairs evenly away from the skin so the tips are lined up BEFORE you trim it off the skin. You should be holding the hairs in the hand you'll be holding them in when you tie them down (typically this is referred to as the "off hand"; the one you don't hold your bobbin in). After removing them, use a fine tooth comb and remove all underfur from the patch you've trimmed. If you are holding the tips tightly, this action should also remove most/many of the broken or shorter hairs.
Depending on the quality of the hair you've started with, the amount of evening and stacking you have to do may be minimal, especially when it comes to bucktail for wings because you don't want an even end on the wing anyway. For elk or calf tail on a dry fly, it's a bit of a different story. For most dry flies, you're better off investing in some calf BODY hair rather than tails for winging material- it's not as kinky and it's a lot easier to get a good, even wing.
The object is to remove from the bunch the shorter hairs, so if you're right handed, you'll start with the tips in your left hand. Pinch tightly on the tips and relax the pressure a little on the rest of the bundle. Grab the ends with your right hand, and pull on them- any shorter hairs should pull out ot the bunch, with their ends roughly aligned. Now, you re-insert this bunch of hairs into the bunch in your left hand with the tips at the same position as the first bunch.
Hopefully this isn't too confusing... but like I said, you can use almost ANYTHING wioth a flat bottom and a smooth side as a stacker. A trick I learned from Al and Gretchen Beatty was to keep a used clothes dryer fabric softener sheet on your bench when tying hairwing flies and periodically run it through your stacker to make it easier to use.
