HI Bernd,
The video above does not show me how to link to a video have it start playing.
I know it is also possible in indesign to have a button link to a specific point in a video, but I haven't been able to find out how to do that from a text link.
so for example. the text could say "watch our video, or click here to learn about subject two".
where - "learn about subject two" takes the user to a specific part of the video, and makes it start to play.