Once you buy the trucks in the produce tab, they will automatically come out of the factory and start collecting potatoes for you. They have a capacity upgrade in the upgrade tab, so they can hold more potatoes before returning to the base. You can hover your mouse over the trucks and see how much profit they are holding and what their capacity is. We added a help tab to the HUD Update 1.1 (KTCDS's suggestion), you will be able to find the truck tip in there! Hope this helps, slayerbp666/Dead Serious Bros.
Thanks for playing~