Remove the 4 bottom screws that hold the side panels. You need the oval drive bit for this.

Leave the other 2 bottom screws in place, these hold the bottom plate in place.

When reassembling, take care not to over tighten these screws. When in doubt, take 1/4 turn back.

Improvement: As these oval head screws are (intended to be) a nuisance, you may want to replace them with similar screws with a more common head.