On most vehicles the cabin air filter is behind your glove box and are usually pretty easy to reach. After removing contents of glove box, unhook the little arm that supports the glove box when it is open, usually this is on the right side of the glove box. Behind the glove box you may see a face plate for the cabin air filter, or it may not have one. Remove this to reach the cabin air filter, after removing you may need to clean out any loose leaves or debris in this compartment. Make sure to replace the cabin air filter in the proper air flow direction and reverse steps to put glove box back in.