How do I change the default program to open the PDF file extension?

In order to set PDF Pro 10 as your default program for opening PDF files, you have two options. Firstly, you can set PDF Pro 10 as the default program when installing the program, as shown here:

Secondly, you can right click on any PDF file, then choose "Open With" and "Choose Default Program...". You can choose PDF Pro 10 (or another PDF program) as your default PDF software: