The best way to learn how to use MultiMarkdown is to start by becoming familiar with the Markdown syntax. The next step is to look at the MultiMarkdown sample documents to see examples of most of the features of MultiMarkdown.
If you are looking for more information about MultiMarkdown, the first place to search is using the search box on the right of this web site. It uses Google, but focuses the results on “official” MultiMarkdown web sites, discussion lists, etc. This will often give you the best search results, if your topic exists in an official location.
I am in the process of moving to a new support system. There’s not much information there yet, but that’s a good place to open a support “ticket” — http://support.fletcherpenney.net/.
If that fails, you can use the search engine of your choice for a more general search.
You can download the User’s Manual as a pdf or view it as a web page. You can also check the User’s Manual on the wiki, which includes a FAQ section. Note that not all sections of the wiki will display properly, since they are written in MultiMarkdown, but Github’s wiki software only supports Markdown.
If you have a bug report, you can submit it at github. (Please check to see if your issue has already been submitted first.)
If those fail, you can also contact me directly using the email link in the sidebar, or you can message me on twitter.