What should I search under?

This seems like an easy thing, but I can't figure out what I should search under to learn how do what I want.

My goal - User has the option of different search drop down box. When they select one answer it filters the remaining search boxes. Once the user selects the information they are then presented with the corresponding View.

Example -
First Search box - Countries (user selects USA)
Second Search box - States (user selects New York)
Third Search box - Cities/Towns (user selects Manhattan).
Then clicks Go.

From there the user is shown a View for the data for Manhattan only.

I will not have more than 3 search boxes.

I have tried searching Durpal.org, but I don't think I am putting the correct terms in the search box.

Any advice? Thank you in advance.