How to search multiple files of specific file type within Sublime Text 3

Question

I would like to search for a string within all *.php files in a certain directory (and its sub-directories) using the Shift + Ctrl + F search dialog.

My guess was to set the search location to:

c:\example\*.php

but that gives an error:

Unable to open c:\example\*.php

Is there a way to perform the search I'm hoping to perform?

Answer 1

C:\example,*.php

In the Where: click ..., select Add Folder, after that select Add Include Filter