Remember, MMD is based on Markdown, so the basic syntax is the same as Markdown’s. In this case, you need a blank line between a paragraph and a list, otherwise, it is all treated as a single run-on paragraph. Yes, you can do tiered lists in MMD, just as in Markdown.
As mentioned in my documentation, I recommend familiarizing yourself with the Markdown syntax before pushing farther into the MultiMarkdown additions. All of this is included in the Documentation folder in the MultiMarkdown download, and on my web site.