Boats don't come with wiring diagrams, which is why you can't find any online. Your only real option is to call Baja to see if they can help. Otherwise, it is a 12 volt dc system. There are a lot of common wires for all boats that have to do with the engine and trim system (mercruiser or volvo), but other than that, boats are too custom to have a standard diagram. Even for each model, they have different speaker, stereo, depth finder, lighting, etc options to include with one diagram.
That is the bad news. The good news is you are on a forum with some of the most knowledgeable boat guys in the world. If you have any questions with specific issues, you will get help in a short period of time.
A couple of tips. Be specific and include as much information you have at hand. It all starts with the engine and drive that you have and falls in place from there.
Other electrical issues are fairly easy to diagnose if you give us the problem. First step is to make sure all connections are shiny clean and tight and go from there.