What is my JV device IP address and how do I know if it's a valid one

Assumption is that the red box is connected via an ethernet cable (or wifi after it was first setup with ethernet cable). Check the screen on the red box and flick through it until you get the LAN settings.

Check the first line

• ✅ A good address is 192.168.x.x, or 10.x.x.x

• 🚫Not a good address: 169.254.x.x . It means that your device has no access to the internet. It has access to your local network but not the internet (it's called a link-local address)

Check how to tell if I'm connected to the internet, and how to connect the device to the internet.