@mrwomble Thank you, that's very helpfull, i will start puzzling around and share the result.

My test situation is Nano+Radio with double relay module and push button for the bell. Relay is powered by the 5V by Arduino, and i have tested this with the example sketch (+modification for double relay) and everything was working fine. The issue i am having is the original sketch (1 bell + 1 relay) is made for mysensors 1.x, and i am running 2.x and have no idea how te rewrite this.

Great how-to for a beginner. But now I'm stuck because of my lack of knowledge to rebuild the sketch for MySensors 2.0. Does anyone already rebuild it and willing to share?