go to a tutorial website like www.tutorialized.com or www.flashkit.com and search for a few key words, such as the ones listed below:
well i would suggest that you first lear how to use buttons since they have the most basic actions like:
on (release) {
play();
}
and also, learn the basic play, stop, gotoAndPlay and gotoAndStop actions
try learning basic hitTest and shapeflag actions aswell...
i would also suggest that you learn the Key.isDown actions, look up a basic movement tutorial for those, and once you have all of the basics down you can start to combine things to do what you want, and maybe start learning something more advanced like duplicating movieclips, shared objects, arrays and functions...
NOTE: all actionscript posted here is actionscript 2.0, i haven't learnt 3.0 yet!