Sorry this is the first tutorial I made x)
I will try to explain you:
The code is the name/id of the event you will send to the others player and the data is a data you want to send with the code.
Like in the exemple at the bottom you send your player.X and in another Event your Player.Y.
Next you can do a event for when someone receive the ''code'' example it will teleport your player on the screen of everyone to the position you send..
Sorry if my explication are bad but I am french and this is hard for me to explain thing in english x)
EDIT: oh you removed your post ?