Assistance building a webhook for inbound fax module

I am building a fax module for an application. I need to build a webhook for the company to send my module inbound faxes. This is the only documentation that they have given me to work with. https://help.documo.com/en/articles/3742441-webhooks

I want to work with a developer that can help me to figure what to build for this webhook to work. We will be communicating via AnyDesk and or Skype to work together on this project. I have attached what I have so far.