How do you get more trucks in 18 wheels of steel haulin

You get more trucks by going to your objectives screen (keyboard shortcut N) and ordering a new truck or by going to one of used truck dealers which are highlighted on the map by a red D. It goes without saying that you need to have enough money to purchase the truck you want to buy. The truck, when purchased, will be delivered to your garage. If you have more than one garage, then you get to specify which garage it should be delivered to.