I dont have a pic, but the small tabs get spot welded to the floor pan, and the top just rest against the vertical side of the floor pan, just beneath the door opening, at something approximating a 45 degree angle. Positioning fore & aft should be determined by the fit of the part. They are not structural, their only purpose is to create a cavity for the rear wiring harness to run thru, and allow the carpet to have a smooth surface to lay on. If you have already painted your floor pan, you could use body panel adhesive; like this stuff: http://www.autobodytoolmart.com/lord-fusor-metal-bonding-adhesive-medium-p-15934.aspx
I have a couple partial pics. Not intended to take it of those covers, but what you can see are in original position. The top one shows a bit of driver side. The other shows passenger side.