and can I still put in the left and right arrow keys like this:
for going to the next scene and previous scene?
Of course you can, you just will have to call your 'knobFunction' (the key definitions) in every scene (and don´t forget your closing brackets... 
)
if (e.keyCode == '39') {
// right arrow
hypeDocument.showNextScene(hypeDocument.kSceneTransitionPushRightToLeft);
} else if (e.keyCode == '37') {
// left arrow
hypeDocument.showPreviousScene(hypeDocument.kSceneTransitionPushLeftToRight);
}
There are solutions, where you have to call the functions only once, you may have a look here: Howto: Navigate Scenes with Arrow Keys (Similar to a Powerpoint or Keynote Presentation) - #4 by MarkHunte