Bolt in roll bar for Blazer

[eighteenninetytwo]

Just scored one (see different thread) and the vehicle I got it from had it bolted in over the carpet. I'm going to bolt it in when the rear has been cleaned out so it can go to the floor. what would i need to do before then and to get it bolted in properly. Do I need anything between it and the floor panels? Do i use EXTRA long bolts that go right through and the nut is under the rocker box?? How do i bolt it to the rear floor and the back of the wheel well? Do I need any extra pates, washers shims etc over and above the plate at the bottom of the bar etc etc??