mounting off road seats in sandrail / dune buggy?

I need some help badly! and kind of asap.

I have a some plastic poly seats in my sandrail right now. they suck and killl my back.

Im looking to get these seats http://www.mooreparts.com/store/product/7328/AC62-...

the mounting points are pretty much the same such as the Beard off road seats and the PRP off road seats

I know i will probably have to do some welding in my buggy

but i have NO CLUE HOW TO START OR WHAT TO DO.

right now i have holy ( from manufacture ) that i stick a bolt through (4 different hole) and its bolted through the floor of the buggy.

The mounting points on the new seats i want to get, have holes at the bottom running "horizontal"

here is a better look

http://www.prpseats.com/Products/12-premier-high-b...

click to see a better view on those mounting points

PLEASE HLEP im clueless and have no idea what to buy or do for the seats

Not sure if this will help me bolt the seats to it, and then find a way somehow to bolt the mounting bracket to the buggy? would that work?

http://www.filthymotorsports.com/PhotoGallery.asp?...