When you press the arrow keys or action, this input is sent to the main player.
Sometimes you will want to have several player entities on screen at once. Don't worry, input gets sent to all of them :)
Sometimes you will want several different types of objects to be able to receive input. Let's call them Player1,Player2, Player3. You can define player as follows in the legend section
Player = Player1 or Player2 or Player3
and then three of those entity types will receive input from the player.
See kettle for an example of sending many inputs to many entities simultaneously.