Thanks for the note! You're always welcome to open an issue on GitHub for help or feedback (links at the bottom of the addon listing). That said, Import and Export work via copy/paste. Export shows you your stash in different forms which you can copy/paste into some other form. Import allows you to paste in any text containing URLs, and Tab Stash will try to find and load the links contained in whatever you paste.

As a pro tip, Import can split your items into different groups if you put blank lines between them. It can also parse out group names from Markdown (so using a Markdown format works best).

If Tab Stash's Import feature isn't sufficient, you can also import directly into your bookmarks using some other method (e.g. another extension) and then move those bookmarks into your stash using the built-in bookmark editor.

Hope this helps!