Dier already spilled the beans about Ange's training sessions/methods didn't he? He was trying to big Conte up by comparing him favourably to Ange in that regard, but reading between the lines it is clear that the latter barely does anything in the way of improving the players.
What we have been seeing on the pitch during nearly the entirety of his tenure only affirms what Dier broadly described, so I take his word for it. Half-pro members of his coaching staff most likely don't know any better. So players, barring a few simple gimmicks such as fullbacks clogging the midfield and low crosses, don't receive any -constructive- direction or feedback from the sidelines.
That's why, no matter who plays where, players look lost all the time. I can't get myself to be mad at them, because I pity them more than anything.