Undo cover retaining fixings - use a phillips screwdriver and a 10mm socket to do this
Remove the cover, place carefully to one side
Undo the two retaining clips
Carefully lift the air filter body
Clean off any debris on the surface of the filter. Replace with a new filter if heavily contaminated
Check the air filter box for debris. Clean out if required. Replace the air filter
Reassemble the air filter housing.