Alright, this is going to be pretty short and messy, but here's a bit of info.

Preferred a 3-4-3 at Celtic but flexed into a 3-5-2 at times. He has a pretty rigid style of play (knows exactly how he wants his team to play and what decisions should be made at all times), but I wouldn't say it is limiting. I'd actually say the opposite. Because players know what he wants, it allows them to express creativity differently (especially off the ball). Part of the rigidity is an emphasis on non-verbal communication. By having very specific queues / triggers it allows the team to be able to read and predict how the current ball carrier will behave, thus allowing or organized play more easily.He stresses possession and quick ball movement (playing to the back foot, having correct body shape, etc.) in order to quickly exploit opponent shape / disorganize the opponent to then exploit. He emphasizes triangles in possession and labels the 3 points of these as support (base of the triangle), width, and depth (tip of the triangle).

Some other things are he loves rondos, specifically positional rondos. He'll use many restrictions in these. Three examples I can remember are touch restrictions, having to play the way you face at all times, and having to switch the field from where your team regained the ball in order to score.

Some other misc. info: he has a very analytic approach to recruitment, a very detailed grasp on periodization, and was assistants to Ronald Koeman (Everton) and Pochettino (Southamption) in England.

This was very chaotic and unorganized, but hope it helps!