Trying to find where the tractor is located on john deere 430 diesel tractor.

Most vehicles, follow the Large wire going to the starter.
Many vehicles battery will be on same side as Starter.

Look for this battery tray:

http://www.ytmag.com/store/parts/pics/wm_R2529.gif

It may be around or under the seat. If it's not there, look below and behind the engine.