After the download is complete, drag the downloaded .jar file to an open instance of Astah. A pop-up will appear asking you to confirm installation, choose [Yes]. If the pop-up below opens restart Astah.
If you see the [Import FreeMind Files] option under [Tools] – [Mindmap], installation is complete!
How to Use
Go to [Tools] – [Mindmap] – [Import FreeMind Files] and select your .mm files (you can import more than one .mm files at once).
FreeMind map will be imported as an Astah Mind Map. All the hyperlinks will be imported also.