Ugh...
There are hundreds of these, and this one doesn't stand out at all.
First of all, there was no back button.
You have very bad grammar and spelling.
You didn't explain this very well, either. "Press F8 and a box will appear". "Name it button so it doesn't confuse you". "Leave Registration as it is."
I think you should have explained everything in the MOVIECLIP PROPERTIES PANEL (aka "Box") rather than having the user skip through everything in it.
You also said to put a }: at the end of the button's actions. That'll create a compiler error! Use semicolons (;) you moron.
You didn't explain any of the button events, except for "onPress". There are many more button events to learn, such as onRelease, onRollOver, onDragOut, onDragOver, onRollOut, etc.
And finally, you taught the oh-so-inefficient way of placing code on movieclips or buttons. It's ALWAYS better to give the button an instance name, and put the code on a frame. For example:
myBut.onRelease = function(){
_root.gotoAndStop(2);
}