Release the two clips on the housing cap, remove it, and thoroughly wipe it with a clean rag. Then, pop out the dust valve and check for dust and debris buildup.
To remove the filters, wiggle them and pull them out.
Wipe out the inside of the housing, but do it with the inner filter installed so it catches anything that might fall into the engine.
Press the filters until they are seated all the way on, put back the cap, and you’re done. The cap on most units includes a top mark. In any case, the dust valve must go at the bottom so that debris builds up there and gradually comes out due to vibration.