Wiring Qubino Flush Dimmer to multiway switches

I’ve bought a couple of qubino flush dimmers. I’ve installed most of them on single switches. However I need to install one more on a multiway switch that’s accessible from 2 points in the room.

I can’t figure out how it’s done, so I made this template. Could anyone with a little more experience help me out, so everything will be done correctly and safe?

If possible, I need to add it to the left switch, because I have a lot more room in the wall behind that switch.