I have a 2019 3761 and have a washer and dryer. My setup is this - kitchen sink = grey 1, half bath sink and toilet + washer drain = black 1, shower and main sinks grey 2, main bath toilet = black 2. Now that does not mean that yours will be the same I have heard the half sink and the washer drain being switched to main sink. It all depends on the installers mood that day.
When you wash immediatly open that tank it goes into, you dont want to forget and do what i did, flood the kitchen area. I have a smaller load machine and 2 washes is definitely too much. I put a picture of my drain levers and noted what to open when washing, on the washer itself as a reminder.
I also have a Reverse Osmosis on the kitchen sink and leave that one open always, except when dumping, Will have to fill it up and flush on occasion.
I am fultiming so the reason for the RO. I also run a portable water softener in the water closet (the new meaning not the old).
oh thats right it is called the convenience center
oh here is link to the brochures with all the info -
https://www.keystonerv.com/brochures