I have VolumioPi 4. Connected to wireless. I want to try to use an ethernet cable instead. How do I get it to change to ethernet? Do I have to do anything to get wireless to turn off? How do I contact the Pi once its on ethernet cable? Thanks,

From my experience just connect the Ethernet port to the LAN. You may be assigned a new IP address. Connect to the GUI using the new IP address. If you want to disable the wireless. Just check the Ethernet port is working via Network Settings menu and then disable wireless.