Thanks for your response. The critical step that I was missing was to preview the site and then start searching for keywords/tags. Now everything is making sense and we can probably proceed with setting up our open data site. I was under the impression that I was going to have to add data listing widget or a dataset map widget for any of our datasets to be visible to website users. In other words, I thought that I had to build the interface (add widgets) for our users to use. So I never thought to try the 'preview site' because I didn't think there would be anything to preview (beyond the banner images, placeholder images, etc that are very intuitive to set up).
I would suggest that ESRI staff add something to the documentation that shows people how to discover the URLs that will access their datasets (e.g., http://mygroup.myorg.opendata.arcgis.com/datasets?q=population&sort_by=relevance). I think the best spot would be between the "Data Report" section and "Design the Layout of your Open Data Site" section, or near the top of the latter. Maybe something like:
"You do not have to add widgets or modify HTML, CSS, Markdown for people to discover data on your site. To understand this, click the 'Preview Site' button and then search for a tag that you've attached to one of your datasets. The URL in browser bar on the search results page should be used as a template to create links to your data in the Design Layout tab"
Or is it already in your documentation and have I overlooked it? I do think videos would be helpful, but I think that somehow working this into the documentation is more important, especially if your weeks away from publishing the videos.
Using MarkDown, CSS, image links, etc will be easy now that I know which URLs to use when laying out the site.