I change my airfilter once a year in late Spring. Here in snow country there is lots of dust producing stuff left on the road after the snow. I wait 'till that is cleaned up by the municipality, that change the air cleaner.
Remove as CopperKat notes above, but it does take a little bit of wiggling. There is however enough room to lift cover and remove and replace the filter without removing any other parts.
Once you have the cover off suggest you look closely at the three locating lugs on the left side as viewed from the front. You will note that they have what I would call 'hooked' ends. Very important to ensure these pass right through the corrosponding 'sockets' when replacing cover, otherwise you will not get a complete seal on the engine intake side of the air cleaner.