2004 3600 Sovran weak starboard starting

[Tantram]

Greetings,

My starboard engine is having a tough time starting, and I think it's likely a bad battery since it turns over just fine if I enable the crossover.

I dropped my head down below to check out the batteries and was a little overwhelmed, not knowing which battery goes to what or even how to get them out of the tight space and replaced.

Is there an idiot's guide to the battery layout or some tips and tricks that may point me in the correct direction?

Thanks for listening to an idiot