Sync variables from Host to people joining to room

so, i wondering if there is a simple easy example of passing a string, int or player variable (or list) from the host or person that created the room to the other clients/players joining the room, for me, i want to pass in and show the Room Name at the top with players currently, example: Room Name:______ Players 2/4

also, want to if there is a nice tutorial that shows a way to add a "Ready Up" button and for all players plus host, and if they are all ready. then Start Game button appears?