I just learned stick last year, so I still remember what it was like. And I just taught my daughter how, well enough that she's now electing to drive a stick as her only vehicle. Dunno if any of this is repeated in the video, but honestly that's a long video to watch just to avoid repeats.
The best advice I can give: jump into the deep end and start swimming. You won't get the hang of it without just doing it. I traded in my only vehicle for the stick car, and had to run errands in it in serious traffic. No time for fear; I had to suck it up and get the job done. And I did, just as many others have before me, and just as you will.
Seat position! No, you can't just drive it wherever the seat is. Your left leg will hate you if you do. If you can, get the seat set up right and then ban everyone else from touching it.
Use that dead pedal. Treat the clutch pedal as if it hurts your foot; only touch it when you need to.
You will stall. Lots. Don't think of it as a failure: it's no more than a temporary setback. And those people behind you aren't in a hurry; their horns are lying to you.

Ditto for smoothness; it's going to be a bit jerky for a bit. The time to learn smoothness is later. Focus on no stalls and no long delays coming off stops.
You will also burn the tires unexpectedly. Don't freak out; just ease off the throttle a bit. Treat *that* experience as a preview of future joy.
Your clutch will survive this trial. If it doesn't, it wasn't long for this earth anyway.
Give yourself plenty of room, since you're still trying to learn the proper reactions to things, and it's hard to judge at first how quickly you can get yourself moving.
If people give you a hard time for not being smooth or stalling a lot, kick them out of your car for a while. If they really need the ride, they can learn to keep a civil tongue in their heads.
Spend some time in empty parking lots in low gears. Launching is the really hard part, so do lots of launches in the lot. Also, practice stop-and-go traffic.
It's probably best to avoid hills at first, especially with stop signs at the top, if you can. If you can't... well, see the advice above about getting the job done.
Don't neglect practicing in reverse. Reverse is strange in manuals if you're coming off an auto. No more coasting backwards! In particular, don't be shy about giving it gas. I still tend to be a bit timid about reverse; there's something comforting about knowing the car will move just by letting off the brake.
Also spend some time on the highway in overdrive, just cruising, no shifting. If you've still got the heebie-jeebies over the car, lots of boring miles will work wonders.
First gear is for launching; never shift down from second while moving.
In fact, don't worry about downshifting at all. There's lots of advice about downshifting; ignore it for now. Clutches are awesome tools for slowing down. When you've got the upshift licked, then start trying downshifting, one gear at a time. Don't skip gears either way until you get a good feel for what gears work at what speeds.
Even while coasting, stay in gear with the clutch in. You never know when you'll need to apply a little more power. Wait a bit on coasting in neutral.
Don't feel bad about sitting still in first with the clutch in. Yes, you'll probably not want to do that when you're more experienced. But you also don't want to be caught in neutral and suddenly realize the light is green; that's worse for you now, since you don't have the reflexes down yet well enough to get moving in a panic, and you're more likely to stall. Been there, done that.
Don't stare at your tachometer, but don't ignore it either. Get a feel for how your engine sounds at the right times to shift, compared to tach readings. Ideally, you'll get to where you can competently drive the car without a tach, just on feel and noise alone.
Remember: sacrifice now for reward later. With experience, manuals are fun and engaging. When I got frustrated with my driving, I'd remember all the times I'd want to pass someone in an auto, and wait as the car tried to figure out what to do when I mashed the throttle down. Never again!
That should do for now. Good luck!