Every nitro RC model has a manual and you need to read it. The manual contains information directly from the manufacturer about setting up, tuning, operating, and maintaining your nitro RC. I see a questions asked on a daily basis in nitro RC groups online that could easily be answered by taking a look at the manual.
Another invaluable counterpart to the manual are the exploded parts views. The exploded views diagram each part of the vehicle and shows how the parts go together as well as the part numbers for each part, which you can search online or take to your LHS to buy a replacement. If you ever need to do a repair or take your RC apart for cleaning and maintenance, the exploded parts views have everything you need to know.
If you bought your nitro RC new, it should come with a complete manual and exploded parts views. If you lost it or bought a used nitro RC with no manual, a quick online search for your nitro RC’s model name (e.g. “traxxas nitro rustler manual”) will lead you to a downloadable PDF of your manual.