Trying to Externally Submit a Topic

I am trying to find an example that will allow me to generate a topic from a submitted form on an external webpage.

I have read this https://www.invisionpower.com/support/guides/_/advanced-and-developers/api-methods/topic-posting-library-classpostphp-r260 and am completely lost on if I am able to integrate this into an external script or not.

What scripts do I need to call, how do I format this...

Thanks!!! @_@