Character in the Center of Screen

Hi guys please help again :angel::confused:

I am making a android platform game in flash actionscript 3. It is a side scrolling runner game.
So what I want is to make my character be on the center of the screen all the time. When it runs the character will always be at the center of the stage/screen. When I press the run button my character runs to the right then the background scrolls to the left.

Please help guys, I am still new in this actionscript 3 programming. I can't find any tutorials in the net on actionscript 3 T_T.