Some of the assertions made by this cleric are correct and some are incorrect (contradicting Quran).
Quran has explained the manner of reciting Salat, Dua, and Quran in detail. Acceptable methods for all three of these are clearly conveyed to us by God and His Prophet. You can easily find the verses if you start a search.
The clerics often mislead, because their source is conjecture and practices of “salaf” and not Quran. Please remember that Quran is the only source of guidance and Criterion for all spiritual matters because it is a fully detailed Scripture.
6:116 And if you obey most of those on the earth they will lead you away from the path of God; that is because they follow conjecture, and that is because they only guess.
Also see 6:114-115, 16:89, 10:37, 7:52, and 12:111.