Create a folder where your Markdown files will be. That folder needs to have the following structure:

 <MARKDOWN_ARTICLES_PATH>
     docs
         *.md
     mkdocs.yml

The mkdocs..yml file contains all the settings for you site. Check more options on https://www.mkdocs.org/

Run the container

 docker run -p 8000:8000 -v <MARKDOWN_ARTICLES_PATH>:/docs jnonino/mkdocs