Plumbing the Argosy

[lea]

Good Day Everyone!
I recently purchased a 1973 26' Argosy that has already been gutted and rewired. The entire insides have been removed. This is my first camper repair/renovation and I need all the help I can get. I've been watching videos and reading blogs from others that have done renovations. I haven't seen any diagrams to show the placement of the water pipes. I'm also confused about the gray and black water tanks. I've seen them under the shower and toilet on the topside of the floor. I've also seen videos where they were hung under the floor between the metal frame. Help, anybody! What have your experiences been and is there a good go-to source for this information?

Thanks in advance

lea