Harrison is currently in his third season on loan at Leeds from Manchester City.
Asked about working with Bielsa, Harrison told talkSPORT: "When I first came here, it was really tough. It was like nothing I'd ever experienced before, in training, in football.
"You'd think by watching us that we do a lot of possession drills and playing five-a-side and things like that. But we don't do any of that.
"So to come into a team and do absolutely nothing like that, to work on these drills and exercises that are so specific - you have to pass the ball a certain way and run in certain directions - it's very interesting to see how Marcelo sees the game and what he wants from his players.
"So it has been very unorthodox to adapt to this way of training and this style of play but, ultimately, it has been great for me as a player to develop and work under him, because I've learned so much, not just on the ball but movements and stuff off the ball.
"As a winger and as a striker, you know how important movements are. So to learn these different things and experience training under him has been great for me and really helpful."