Simple Fix for an IIS Techie.

I have a dedicated server running IIS 10 on Windows Server 2019. I host several websites and want to add another site to use temporarily as a test site for a major upgrade to the main site.
I attach a screenshot that shows an IIS error that needs fixing so I want someone to help me fix it - via a zoom call where I share my screen and do what you tell me. I cannot give access to the server.

As a separate job, I want a step-by-step process guide for setting up a new site using IIS - a simple Word document with screenshots. I have an old one but it is incomplete.

Thanks
Steve