I have this wiring configuration. Any help on wiring in a smart dimmer would be great.
You will find the wiring diagrams in the Inovelli help site:
Add additional Aux switches using two of the three conductors of the 3-wires between the switch boxes.
I am presuming the line and load are a switch loop from the light to the first box. If your line and load are in separate boxes, individual conductors perhaps, we will have to adapt this.