There is a whole separate universe of fancy shots. Those are shots that no average player would ever use in a game. It is possible to freeze the cue ball to the end rail and draw it back from a ball at the other end of the table. That shot and the associated technique are not useful to you at the present level of your fundamentals. Neither is the demo in the video posted.Wow, that guy really did stroke down! I thought the stroke was supposed to be level? ...
To get draw, you need to hit the cue ball low. To get a lot of draw, you need to hit the cue ball hard.
You will also need to chalk. It could be that chalk is your whole problem, but that's hard to diagnose over the interwebz. Do you look at your tip each time you plan to put spin on the cue ball?
You don't have to be level, although it may help. You don't have to come straight through, although it may help. You don't have to hit the cue ball at peak stick speed, although it may help. You don't have to avoid dropping your elbow before contact, although it is almost certain to help. You don't have to follow through the cue ball, although it may help. You must hit the cue ball low and you must hit it hard if you want lots of draw. I can draw the ball violating all of the "may help" suggestions if I'm forced to, but I find it a lot easier and consistent to follow them. I can't draw the cue ball without hitting it low and neither can anyone else. I can't get a lot of draw without hitting the cue ball hard, and neither can anyone else.
"Hard" is a relative term. You can see how hard you are hitting the ball by shooting the object ball straight up and down the table -- not into a pocket. To draw the cue ball back two diamonds, you will probably drive the object ball two table lengths when you use your very best soft draw. To draw the cue ball a table length, you will probably drive the object ball three or more table lengths.