Uh.. you know. [ Look, it's a vague answer - accompanied by a vague hand gesture, even - but what else is Inigo supposed to explain about what happens when you step on the panel at the right time? It's just how the game works! It's knowledge that came to him so innately back in Diagad, thanks to the fake memories, that he's having a hard time explaining it. ]

If you don't step on the right arrow at the right time often enough, the game ends. Game over!

[ .. does that make it a little more clear? He isn't sure. All he can do is demonstrate as the song plays on the screen, moving his feet and stepping on the arrows in time. ]

And you don't need to look at the arrows, they're just in logical order! To the front, to the back, to the left and to the right!