@telumire has two great tiddlypwa videos showing how to create a new wiki and how to import an existing single-file wiki.
To get a single-file wiki it should work to open your node.js wiki in your browser, visit the $:/core/ui/DownloadFullWiki and click the download button. There are lots of other ways to accomplish the same.
Then follow along with the second video using your single-file wiki.