Message device to device using Firebase

[Massimiliano 0]

Hello everyone,
I would like to understand how i can use the specific FUID of a user registered on Firebase to send message from another user. I'm using https://github.com/SchneiderInfosystems/FB4D (posted in this forum).Obviously, now, i can only send messages between 2 clients with same user (same uid). Maybe i did not understand well their coudcliboard, present on their github. An advice would be very helpful.
Best regards