Starting with binedit is kind of doing it the hard way. The place to begin is with a simple repaint. Then, as you get used to things and see how the programs and files come together, you can build up to the more complex things using binedit.
http://mtm2.com/~mtmg/repaint/
A word of encouragement. All the stock trucks are replicas, and they are all basic paint jobs. It takes time patience and practice to get up to the level of the seasoned/veteran makers.
Take things one step at a time, and if you encounter problems just ask. Just let us know where you get hung up and we'll try to find answers for you.