This isn't very indepth but here's my ramcharger seat install.
I hope you can see the factory bench seat mounting holes the two outer holes for the buckets use those same two holes. For the other two holes I just drilled them into the floor n put some big washers on the bottom then bolted the seat brackets down.
I had to trim about two inches forward however wide the brackets went then about two inches off the back of the carpet for them to fit right.
I have a pic somewhere with the pass side seat bracket mounted in but can't find it anyway here is the end result.