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.
Install is complete if [M+] tab is added in the “Extra View” below the diagram editor.
If Extra View is not open, go to [View] – [Show/Hide Extra View].
Also, install Helper for M PLUS which helps settings easily when you use M+ plugin.
How to Use
Please refer to the Plug-in author’s website for instructions.