onKeyRelease or press: create a button and in the instance atributes go to "+" add the even that you need and then click on the on mouse event (Release) that will bring up options on the right and all you have to do is sellect "key : whatever"
on multiple key press: crate two buttons. do as above for each one Ex: button1 "arrow left", button2 "arrow right"
that will let you press multiple keys at once.
BUT it's not exactly what I meant. I'm aware of making KeyPress buttons. But if you create 2 or more simple KeyPressbuttons, this will happen:
If you add an action, like increasing the x-coordinate of some object to button 1, and a second action, like increasing the y-coordinate of the same object, to button 2. Then if you hit the first keypressbutton by pressing "right arrow" or whatever, the object will move to the right. Then again, if you press the second button a bit later while still holding the first key pressed, it seems like the signal which is send from the keyboard to the computer or swf-file gets overruled by the second press (i.e. pressing the second button). So only the y-coordinate of the object will increase, but what I want is to increase both the x- and the y-coordinate by pressing both keys at the same time....
I see now, you want to hold down first button while you press or release the other and do not effect the first button state in any way.
That is hard to do. Maybe even imposible depending on the details. If I will figure out something I will let you know.