On the fuse panel, find a fuse that remains hot, connect the wire from the VM marked POS or +, attach it to the fuse holding clip. locate any point that is grounded and connect the NEG or - wire. I don't recall where I did.
Easier done than described.
I sure didn't explain myself very well. I want to monitor the house battery not the chassis battery. Thanks.
That's a very nice looking installation. Far superior to what I rigged up on our 210P. The important thing is you now have a convenient source to give you the voltage of your batteries.
Here is an easy to understand color chart that I printed out years ago and keep handing, although over the years I have pretty well memorized the voltage to percent charged depicted here.
https://www.rvtechlibrary.com/battery/bat_volts.php