I would like to ask for a precise, step-by-step solution to the following matter, someone should not describe in general terms how to solve the problem.

We live together in an apartment with my wife. We bought an ARC+Sub and a Roam. I registered my own username and put all three units into one system. I named ARC+SUB Living Room, and Roam runs as Sonos Roam.

The situation I want to solve. I would like to listen to the Rolling Stones on TIDAL on ARC+SUB in the Living room, for example, with my Tidal subscription.
My wife and I listen to the Beatles from Spotify on the Sonos Roam in the other room with her Spotify subscription.
How can this be solved so that the system does not crash?
What does my wife have to do to be able to do this?
Does it need a separate registration with Sonos?
Please explain to me as if I were a five year old.