I don't know that car, but typically you will need to release and move the 2 constant tension clips that secure the inlet ducting and the outlet ducting to the air filter assembly, then it should lift-pull upwards off the fixings, check to make sure that there is not a small hose that needs removing before lifting the air filter assembly away from the car.
Edit:- to explain better, typically, the air filter assembly is fixed to the top of the engine by having 3 rubber "donuts" built into the underside of the filter assembly, and they get forced down over ball ended posts, so lock into place.