Once you know the engine, you can:
* Consult your owner's manual: This is the best resource. It will have diagrams showing the location of the spark plugs.
* Use a repair manual specific to your year and engine: Chilton's or Haynes manuals are readily available and will have detailed information including diagrams and instructions.
* Search online: Search for "[Your Engine Type] 2003 Dodge Ram 1500 spark plug location" on Google, YouTube, or a dedicated automotive forum. Many videos and images are available showing the process.
Without knowing the engine type, it's impossible to give you a precise location.