I buy and sell lots of boxes and the process in not hard and don't sweat it too much.
I have a liftgate, so getting it in the truck is easy for me. But the strapping is what you seem to be asking about. I put a piece of card board and foam on the front edge of the box and roll it up against the front edge of the bed. Then I take a 1 1/2 strap hook it to the front tie down (mine are at the top edge of the bed) and wrap the strap around the back of the box (another piece of foam) and to the other tie down on the front edge of the bed. Then I crank it hard. Never bent a box yet. If it has a rubber mat on top, take it off or it will blow off, if it has a wooded or SS top, I run another 1 1/2 strap across the top. I have moved dozens of boxes this way with no problems. If you don't get it tight and the box can wiggle or move a little, that is when you get paint damage. i normally take most of the tools out cause the slides don't like all that weight bouncing up and down the road. Also lock the drawers so they can't come open.
One good heavy strap will do the job on a double bay box as long as it it strapped up against the bed.
