Unfortunately I can't give you much help regarding you tube videos. I'm sure there are many and if you seek you shall find.
However, the dirty secret about knife technique is that while there's a lot to practice, there's really not that much to know. The hardest things to learn are how to hold the knife, how to hold the food, blocking, and what the basic cuts are supposed to look like.
Most people find the "pinch grip" is the most effective way to hold a knife for chopping. It takes a minute to learn, and a few months to get enough practice so that it no longer feels like an unnatural act. Eventually, it becomes the way you pick up every knife even though it's not the most effective grip for every situation. It's utility is in controlling the line of the blade, and keeping your knuckles off the board. In a situation where you need a lot of feel, like boning, it's not helpful. Then -- whatever works.
The Henckles website has one or two videos that show the basic "pinch grip," "claw," and "cut and retreat." The demonstrator has excellent knife skills, but doesn't move so fast you can't see what he's doing. One of the problems with people with really good skills is that they tend to show off rather than teach.
Start out by putting your chef's knife on the board, then picking it up and holding it the way you usually do. Look at your knuckles, you'll see they're facing straight down. Put the knife down again grasp the blade gently with your thumb and forefinger, just in front of the handle (or bolster if the handle has one), as though you were gently pinching it. Hold it just tight enough to pick it up, then wrap your third and fourth fingers lightly around the handle. If you take a look at your knuckles now you'll see they're pointing down. That means you can chop, with the handle over the board, but without rapping your fingers against it. Still with the very soft, four-finger grip, try chopping your knife up and down against the board just to prove it to yourself. Wrap your pinkly around the knife and try a chopping motion again. Now you're pinch gripping.
I had you hold the knife in a very soft four finger grip to make a point. There's no need to hold a sharp knife any harder than that. The keenness of the blade does the work. If you can't sharpen your knife adequately because of limitations in your skills, your sharpening kit, or your knives themselves, there are limits to how far technique will take you. Sharpening should be your first priority.
You should learn to "claw" your food at the same time you learn how to pinch. Put your offhand (not knife hand) flat on the board. Now leave your finger and thumb tips on the board while lifting the palm to make a "spider." Rock your palm forward so your knuckle bones are slightly ahead of your finger tips. That is, the tips are curled in. For what it's worth, that's the "claw." Pick up your knife again, and put the flat of the blade against those knuckles. Curve your thumb in so it points toward your little finger. Then rock the knife up and down in a chopping motion. With your finger tips curled in you can't cut yourself. That allows you to use your offhand as a guide and guage for making very small cuts.
That thumb thing is a "fine point." When the food you're cutting gets to be small, the tendency is to push it along with your thumb -- as long as your thumb points towards your pinky, it won't ever get where the knife can reach it.
A video isn't going to teach you the difference between alumette and julienne, or the precise dimensions of medium dice, fine dice, and brunois -- because there's no real agreement except in the progression of sizes of from medium to brunois. Some kitchens have alumette finer than julienne, others some vice versa. The benefit of live teaching is not so much watching the demonstrator, but having the demonstrator watch you and help make corrections.
If you have questions about how to use a knife -- including what's the right "classic" knife actions in a given situation, I'll be happy to answer.
PS. If you're looking to buy knives, as well as acquiring skills, I suggest staying away from the top German knives. Many German knives are quite good, but the whole type has become obsolete. There's been a revolution in knife design towards ligther weights, better knife steel, and more agile shapes led by Japanese knives. You can do much for the same money from Japan than Germany.