To put an actionscript on a button.
1. put a stop(); command on the first keyframe, or , if your splash screen is animated, put it on a keyframe at the amount of animated frames.
2. Select the button.
3. Open the actionscript panel.
4. Type in, or just copy and paste in from this page:
gotoAndPlay("name of your scene", 1);
Be sure to put the actual name of the scene we'll click to in quotes, and leave a space before the frame number in the scene you want the button to take your viewer.