One of the gas tank straps is gone, I need to.

Really tough! You poke the end into the slot, turn it 90 degrees, and bolt on the other end. The hardest part is removing the old bolt if it is real rusty. Soak it with "PB Blaster" or "Rust Penetrant" from the Chrysler dealer's parts department. Those are both real good penetrating oils. You can remove an old strap from a car in one of the pick-your-own-parts salvage yards to see how they come off. Do a search for "Pull-A-Part" and see if they have a yard near you.