How do I add a simple child page?

I don’t know why this is so difficult for me to wrap my head around but I can’t figure out how to add a simple child page to a normal page/section or whatever it is called.

Can anybody help me figure out how to add a child page to a “one-click-hugo-cms” site? There is clearly something I am not understanding and I could really use somebody to walk me through it.

Here is the site I’m working on…
hugo.cmarabate.com

I tired everything on https://gohugo.io/templates/menu-templates/ and was able to get the top level nav items working. It looks like it is also setup to pull in all child pages as sub-navigation menu items but I don’t understand how I’m supposed to add a child page.

I’ve looked all over docs and I can’t find anything that clearly explains to me how to do this one thing that I thought would be easy.

I am sorry but the question is too broad and fundamental in its scope.

This is a support forum for specific questions.
We cannot walk you through the process of learning Hugo.

Please have a look at the Requesting Help guidelines and the Netlify Docs for their CMS.
Once you have a concrete question you can always post here.