@Straticah When you create a node template file using the file menu item, it will be picked up automatically by the exporter.
There's no use for adding a code editor for the C++ file, just go in the IDE project of the dll and edit the C++ in Xcode / VS Studio:
Create a C++ template file
Export the DLL
Open the project (in DspNetworks/Binaries/)
Edit the C++ code, debug in Xcode / VS by attaching the debugger to your HISE build.
Once you've set it up, the workflow is pretty similar to the usual workflow for C++ coders.