It’s hard for me too, but I think I got it. Here is what they said. If my interpretation doesn’t work(because most likely I will make a mistakes) then set the speed to lower or add subtitles. 1st get an opening that has the style you like, for example if you have an aggressive style then choose an aggressive opening and ect. Not from the vid: The way to know your style is while you play analyze it to see if you played with more attack or more solidly. To find out the best move for your preferred opening you need to go to explorer in the Lichess database and check moves that are played often and do not click the master version because that is too advanced. Now put what you learned into excel like for example with the queen’s gambit you put 1. d4 d5 2. c4 and other moves and go to chess compass(search on google) and put the moves you typed into excel and put it into chess compass and wait for the engine to get the best move and then add to your moveset and repeat. If in any case you have 3 moves tochoose from then just choose one with the middlegame that you can play and not for GMs to play midgames and to find out the midgame you have to go through the moves.
Not from vid just me noting stuff for you: you should also try to understand what you are playing because if you don’t the middlegame plan will be very hard for you to play and also the more you know of an opening the worse it gets because usually the more theory you know the harder the middlegame will be and this is why I prefer system alot more because it does not give a GM level middlegame.
any expert explain this. this is too fast to me. i cant understand this trick. i think its different from others. https://youtu.be/Ft2-xu--9fA