Hi,
It's ok, once you pass this concept, you'll feel a lot more in control.
I'll try to be concise:
Computer A
Computer B
Player A
Player B
When Player A starts your game on Computer A, The prefab you instanciate for Player A will return "TRUE" for the "Is mine" action.
When Player B starty sour game on Computer B, Photon will want to show Player A, and will instanciate the same prefab it did on Computer A, BUT this time the instance of Player A will return "FALSE" for the "Is mine" action.
so "is mine" means: is this prefab instance is owned by the player playing on this very computer, or is it a represenation of another player, playing on a different computer.
Does that make more sense?
and so, now comes the critical use of this information, since Player A and Player B will share the same prefab, use the "is mine" information to shut down input control when it doesn't apply. here is simple bullet point:
Computer A - Player A instance : is mine = true : WRITE data : User input ON
Computer A - Player B instance : is mine = false : read data : input OFF
Computer B - Player A instance : is mine = false : read data : input OFF
Computer B - Player B instance : is mine = true : WRITE data : User input ON
Bye,
Jean