starting from the front of the car, there is the half of the airbox that is bolted to the front frame next to the radiator. I assume you cut that out. the next part you see is the air filter, and then the other half of the airbox, which connects to the rubber intake hose. this is the half of the airbox that needs to be gutted. look around the edges, and you'll see round plastic bumps....cut those off, or drill them out....those are plastic welded spots that hold the inner goods in place.... once you remove the weld spots, the whole inside comes out, and your airbox is gutted. If you use a drill on the welds, like I did...be careful because the drill will bite, and then drive itself in the hole, and it can crack the airbox. You don't want to crack this half of the airbox, because it'll allow air to bypass the air filter.
good luck. I hope I explained it right I'll get you a pic of the inside part that is removed from the airbox.