idk if this is the right forum or night but here goes. I just bought a bri mar dump insert and i have never had one before. I need to know how do you bolt it in do you go through or do you use the bolt holes next to the crossmembers that are in the bed underneath??? also this is going in a 2002 chevy 2500hd again i dont have the bolts but do have the brackets and their slotted so im figuring square it up and get idea of where to drill???? Any advice would be much appreciated thanx!!