Hey, no problem.
Those system expressions compare vectorX of the platform behavior. I changed it so that any time the player is moving left, it will point left, and any time the player is moving right, it will point to the right.
I just realized that this was not necessary, I was using the arrow keys by mistake. But it will still benefit you to leave them in as you should support multiple controls, and you will not have to duplicate events.
Also, it is very good to know how vectorX and vectorY work.