Help needed with Server Side Verification

[Theom50]

I've installed the Prosopo widget on my website's contact form by including the Javascript resource in the section and the widget in the form.
I've read the instructions but I don't understand what, if anything, I need to upload to my web host server. Is it a separate file, either Javascript or PHP, or another line of code in my contact page?
Any help would be much appreciated, thank you!