Here’s my suggestion,
Watch the way 90% of people do it, and don’t do what they do.
Most people give the car way too much power when starting in first, if on a hill it’s one thing, but if the surface is level, you shouldn’t hear the engine racing at all, it should sound like an automatic starting out.
If you stall the engine occasionally, it makes you look like a fool, but in fact it means you’re doing it right; you aren’t over-compensating with the throttle.
You should be able to start the car out on a level surface, and get it rolling by slowly releasing the clutch pedal, there is no need to give it any power at all.
I think being able to master the 1st start is the main foundation of learning this.