Hello,
As Koen says, you should be able to translate a plugin via the AMOS UI or by uploading a file. However, it seems that Kopere Dashboard is marked as experimental, and so the plugin is not available in AMOS (see comments in CONTRIB-7019) .
The good news is that Kopere Dashboard will be removed from the experimental category soon (CONTRIB-9833) and you will then be able to translate it. Thanks for your willingness to share your translation.