Sorry, missed this.
I cut it very carefully, the plastic stick on you see peals off the remote that comes standard, and I first marked the mute button, then measured for the other two. After that, a quick guess on size and I had drilled the holes, and mocked the circuit bored with the lights and switch up. The plastic stick on gives you room for error, so even if your holes are a bit too big they get covered up.
I rigged mine in with a combo of epoxy and duct tape, and it has held strong for two years, admittedly it isn't what I would call my finest installation, but I use the mute button on the RD primarily now because of how easy it is with the windshield on the 4runner. When I had the same setup on my Accord however, I had a much better install, and it worked very well as the primary mute button. With some patience something like that isn't too hard, and it looks very slick.