Right-click on your scroll-up button, and select
Actions.
There's a new command that we're going to use: the
scroll command, which predictably tells Flash to scroll whatever object the command is pointed at, by whatever increments we set.
scroll is a value of sorts, so it needs to be told how much to scroll.
You can find the command by going to:
Objects->Movie->TextField->Properties->Scroll. Double-clicking it will insert the following code:
on (release) {
.scroll;
}
You may want to change that on (release) to another on command based on the behavior of your mouse, but for a simple scroll it will serve adequately as-is; the box will scroll up or down by one line with each click.
See that red highlight? That's Flash's way of telling you that something's missing, and we need to add parameters.