Here's the entire formatted file mathpaddemo.txt. The web page is pretty darn big, but I constructed it easily from within Mathpad merely by saving the entire file as an image. Since the file is formatted, you don't see the stuff that you type. You'll have to download Mathpad to see the "raw" file. Here's the first few lines of this "raw" file:
| \bd\center Introduction |
| IMPORTANT - You should use the keyboard to scroll in this file, the vertical arrow keys or page up and page down. You can use the mouse to scroll, but until you gain familiarity with Mathpad, keyboard scrolling is a better choice. |