Hiya!
First of all, welcome to community! We’re super happy that you’re trying netlify and I promise this won’t be confusing for very long.
Secondly, you do not need npm (node package manager) if you are only deploying a html/css site. In that case, all you need to do is connect netlify to the github repo. if you have an index.html at the top level of directory that is your github repo, you do not need to set up any directories, and you can just leave these settings blank:
Screen Shot 2019-10-14 at 09.46.52
the build command and publish directory refer to sites that are generated, for example, with a static site generator such as Gatsby or Hugo, where javascript is processed and turned into html. In those cases, we also need to install developer tooling and dependencies to run those processes. That’s what the package.json is for - it tells npm which packages are needed for the particular chain of build processes you’ve set up for this site. They can vary really widely, so dependency managers like npm only go fetch the ones needed for this specific situation. the list of things you need is in that package.json file.
tldr; you don’t need a package.json,one if you are manually building a static site with html and css (and JS, such as, for example, jQuery to do DOM manipulation and other stuff), as you are not using npm as you don’t need packages or a build pipeline.
Does this make sense?