I think the idea is to learn from those tutorials, then write your own code. You can't expect to just find a piece of code that exactly matches your needs and be able to get away with nothing more than a copy/paste, then collect your paycheck.
If you make an effort to write your code for your autofill text box, but still need some help, just post what you've written and describe where it is not quite right and I'm sure the volunteers here will be happy to help you along.