I have looked up on the web to deepen more about digimesh and know how to implement it but I just found superficial information.
I don’t know which Digi Mesh module you have but one of the manuals can be found at https://www.digi.com/resources/documentation/Digidocs/90002277/
In general, the addressing on Digi Mesh is 64 bit. So you use the Serial number as the Source address. When you want to send data to a specific module, you put its Serial number high and low in the DL and DH field of the sending unit.