If we want to line up several objects and have them evenly spaced, one way is to use rulers and guidelines.
From the menu select View, Rulers. You will see rulers on the top and left. When you move the mouse over the stage, a small line on the ruler shows you exactly where your mouse is positioned.
You can add guidelines by dragging out from either the top or left hand ruler and drag the guideline to the position you want. You can clear the guides by selecting view, guides, clear guides from the menu.
Guidelines are not seen when you run the movie, they are strictly to help you draw with more precision.