¤ select your rectangle tool,
¤ cancel-stroke/outline (from top of colorchart),
¤ and select white as fill.
¤ Draw the whitekeyon the stage, just to an approximate size.
Size your drawing to an exact 15x80 with Info screen [ Ctrl + I ].
¤ While whitekey is selected,
copy to clipboard [ Ctrl + C ] for other buttons later.
¤ Move this first whitekey to the left edge of the stage. Buttons will be automatically aligned later so you need not worry about exact position.
¤ With this first whitekey still selected,
press [ F-8 ] to open
Convert to Symbol screen.
¤ For
Behavior, check:
Button. This really doesn't need a name.
¤ The result is your first Button Symbol on frame 1 of layer c3.
Later we will add sound to "over" and "down" button states,
plus a downwards-nudge to indicate a "hotspot".