From there just simply enter your desired title, then the message section would be whatever you want to write about, with the newbie intro just tell us about yourself, your truck, how you like it and what plans you have for it. Finally just scroll down and press "Submit new thread" and there you go.. All done.
If you have any troubles just let me know
To start a thread you would go under the subforum section you want. I would recommend making an introduction in the newbie checkin section and tell us a little bit about yourself. Just simple click on the subforum, or you can find it right HERE ..Right under the newbie how to section there is a button on the left side which says " New Thread". Just simply click on that and a blank thread pops up.