Transfer data from client to server on open level?


I’d like to know how can I transfer data in variables from a client to a server.
This is how I have things set-up:

I have one listen server that is waiting.
The client just calls open level node and in the level name I just type the IP address of the listen server.
Now I’d like to know how can the client when he is in the lobby transfer the chosen data (such as name of the player and color) to the listen server.

Note: I’m not using any online subsystem.