Its a philosophy based on very fast passing and counter attacking, that switches the importance to movement and creating space when the opponents sit back.
Bielsa is not afraid of letting his team try to hit long balls to Llorente but generally prefers the rest of his players to quickly pass along the floor and get forward quickly.
Zonal Marking put up a great article detailing some of Athletics movements on his website if you want more details.
Generally Bielsa prefers having one more defender at the back than the opponent has strikers, he likes playing midfielders at the back to help with distribution, attacking players willing to swap position, very high pressing, very quick passing (usually along the floor), midfielders who he uses as defenders also step out from defence with the ball.
I would say a lot of the players will need 'move in to channels' and maybe get players in the 3 to swap positions with each other, they use a very fluid style but it will be difficult to impliment this within the game.
