Do you have a good sized plastic box on top of the engine that says BMW on it. If so, see those metal clips holding the top on? Pop those clips off and the box will lift right up. Now, see that dirty, dusty pleated "paper" thing with the rubber gasket around it? That's the air filter. Remove the old one and replace with a new one. Make sure the new one is seated properly all around. Replace the top and make sure it's seated right and push the retaining clips back on.