Then attach a piece of wood to the ropes so that your dog gets used to pulling something behind him. Finally, add some additional weight to the block of wood. Finally, you need to add the cart. In many draft tests, the dog is required to perform both on and off leash. A cart can be something fancy like the sulkies that you see in horse harness racing or it can be something simple that is made of wood.
Wagons are often modified versions of children's red wagons.