Build a secure bridge that can withstand the weight of the truck as it goes from one side to another. Purchase parts to construct your bridge with your limited money. Once you have constructed the bridge, instruct the truck to drive across it. Keep an eye on the beams as the truck passes; red indicates that a beam is under a lot of stress. Good luck!
Use your mouse to build bridges. Click the play button on the upper left side to see if the bridge is stable, if not you can edit it. Turn the go lights on to get the truck moving.