Presumably you haven't taken the top cover off the engine yet or you probably wouldn't be asking this question.

Pull up on the top cover from the back end and then the front end. It may be stiff at first because there are four clips underneath that go over rubber mounts. Get your hands under the front or back end of the cover (both sides) and pull up gradually until it comes loose. Take the cover completely off including the air intake tubes that go to the front of the car. Those round air intake tubes just slide in and out at the two ends.

Once you have the engine cover off, turn it over and separate the filter box from the cover itself; there are screws that you will have to remove. Once this is done, you simply replace the stock filters inside with K & N type. Same size, same direction.

Then put everything back together again.

Hope that helps. The toughest part is lifting up on the cover and removing that for the first time.