All you do is pop off those bolt covers on the sides - there's four of them. Now, to be frank, I did not re-bolt them back down - that's another project for another day. In the meantime, I just have mine sitting there, but moved a couple of inches forward, on the floor, but it's not exactly "secured", or anything. I don't have kids, and I would never let anyone sit there on that seat, to begin with - no way am I giving up that armrest, LOL. Therefore, it's really not a big deal, if it isn't secured to the floor - it's heavy enough, and doesn't move around at all.
Later this year, I'll get around to securing it with new bolts, etc. But, I'm 5'10" and with the seat where I need it, it was too far back, so I said screw the bolts, and moved it forward. If you do this, be careful not to move or pull it too far forward - you've got wires all up in there, for your USB's, SD card, 12V inside and 12V on the back of it. But, it's SO much nicer having it moved forward. Chevy must assume everyone is 6'3", or something. It also makes the back seat much roomier, as well.