On the website of Ketron-Musixx there is a tutorial for connecting keyboards of the current SD series or the Midjay PRO with SongBook+.

(For SD9 - SD 90 - SD60 - SD7 - SD40 - MIDJPRO)

The original is only available in German language:

Download-Link (in German, directly von https://www.ketron-musixx.de)

The document attached to this article is a version translated by machine (DeepL.com).