Dual battery set up on 18 212x

[Solarz11]

Ok guys kind of a noob question but can you explain to me how the dual battery set up works. I understand one battery is for starting and one powers accessories and what not but do I leave them both on all the time? Should I turn one or all off when it’s not in the water? What is the emergency parallel one for and when do I use it? I I’m still waiting on delivery of my boat so I’m just trying to educate myself on everything before it arrives. First boat with a dual battery set up. Thanks in advance.

 

[jsg73]

Both batteries on when using the boat.
Both batteries off when leaving the boat for a while (like a day or more).
Yellow switch is for getting the house battery to jumpstart the starter battery.