I suspect that you have no **Generate Fabrication File (Gerber)** button because you are working on a **PCB Module** and not a **PCB**. To continue, I suggest that you: 1\. Save the PCB Module as it is; 2\. Open a new PCB; 3\. Save it with your desired name and then; 4\. place the PCB Module that you have just saved into the PCB that you have just created; 5\. Save the PCB and then continue working on the PCB and not the PCB Module\. Note that if your PCB Module was created from a Schematic Module than you will have to do the same steps to convert the Schematic Module into a Schematic that you can then use as the master document for the PCB (so that you can cross-probe and do updates from schematic to PCB).

Ok, thank you very much, it works!