* Locate the air intake system: Look for a large, rectangular or cylindrical housing connected to the throttle body (the part where the air goes into the engine).
* The air filter is inside: The air filter itself will be inside that housing. You'll usually need to open a lid or remove some fasteners to access it. The air filter is typically a pleated paper element.
Consult your owner's manual for the exact location and instructions on how to access and replace the air filter. A diagram will be helpful. Many online resources (like repair manuals sites) also have diagrams showing the location if you have difficulty finding it in your manual.