The zoo is trying to expand so it will need a lot more animals. You are assigned to get the animals and deliver them to the zoo. You need to make sure that none of the cargoes fell off while you are delivering them to the zoo.
Use the mouse to put the cargo or cargoes in the truck. Drive as fast, but as careful as you can. Make sure that the animals are well secure enough that they won't fall out of your truck and get them to the zoo safely.