Note: In the real world of editing in Flash there may be times when you will need to lock all layers except the one you are targeting. This way you are sure to select only the canvas objests you want to select.
In Flash 4 select F8 or go to the menu and select INSERT > CONVERT TO SYMBOL.
Note: The editing features in other versions of Flash are layed out differently. For example in FLASH MX 2004 you will select either F8 or from the menu MODIFY > CONVERT TO SYMBOL.
Select BUTTON for this symbol type and name it anything you like (e.g., button_1)
INSERT IMAGE 2 HERE