Transfering data in Manage different screens tutorial

[MrOnlineCoder]

Hello. I found This  tutorial (https://github.com/SFML/SFML/wiki/Tutorial:-Manage-different-Screens) nice, but there is one question: how can I transfer data from screen to screen? For example, I have 2 screens: FindGame and Arena. FindGame screen searches an opponent online and has to transfer IP of server to connect to Arena screen.