If I had to guess, I would say it means to put product (throw) onto the shelves from the pallets (delivery truck).
To throw a case means throw whatever is in the case (box) onto the shelf. So to throw a truck would be put all the product that came on the delivery truck onto the shelves.

To pull the pallets from the truck is usually called "pull the load". At least at my place. Then you normally take the pallets to the isles where you break them (take the boxes off the pallet) and either put them on U-boats, take them to the isle and work them - throw the load to the shelves. Or you can wheel with a 2 wheeler to the actual place where the product is on the shelve and you spot it. Meaning you put a stack of lets say pantene shampoo exactly where it will be on the shelf. Hope this helps.