How to make chracters move in flash using the keys

First, make a movie clip, whatever you want to make the character look like. In that movie clip, put in this action script:

onClipEvent (enterFrame) {
    if (key.isdown(Key.UP)) {
        _y+= -5;
    }
    if (key.isdown(Key.DOWN)) {
        _y+= 5;
    }
    if (key.isdown(Key.RIGHT)) {
        _x+= 5;
    }
    if (key.isdown(Key.LEFT)) {
        _x+= -5;
    }
}

Then, test the movie and use the up, down, left, and right keys to move your character.