Protect Content - Upfront/Spirit - Is there a place where I can find more documentation for set up?

Mainly looking to see if there is more documentation on setup for Protect Content.

The issue that I'm trying to over come right now is that I have set up Protected Content - chosen the content to be protected - the payment gateway setup - added the url for the custom payment button - the signup process is smooth. When I click on my payment button I get a warning for 'untrusted site' (which I understand is a ssl cert issue) - but when I accept the cert I am redirected to a 404 page on my domain.

Currently I'm working on solving the ssl certificate with hopes that is what is causing this.

Thank You for any advice & direction! -Jason