PHP programming forum. Ask questions or help people concerning PHP code. Don't understand a function? Need help implementing a class? Don't understand a class? Here is where to ask. Remember to do your homework!
You will have to be more specific. If you need to know how to add a button, it is a basic HTML element and you can learn how to add it to a page in any HTML tutorial, such as at [url]html://w3schools.com[/url]. If you know that, but are asking about the code that produces a "preview", you will have to tell us what you mean by "preview"--that could mean many different things.