How to start run_app_via_uplink?

What I’m trying to do:
Run my server-side code in debugger (Wing IDE) under Windows 10 via run_app_via_uplink, as suggested in App’s __init__.py.

Thus far, I have used Git to get a local copy of my source code, and I seem to have the venv and environment variable set up correctly. At least, anvil’s code isn’t complaining about them.

What I’ve tried and what’s not working:
Instructions say to use
python -m anvil.run_app_via_uplink YourAppPackageName.

Since the only place to set a package name is in Anvil’s IDE, there I have set the App Package name as PRIMA_Base, and I am using PRIMA_Base in place of YourAppPackageName.

However,
anvil.run_app_via_uplink
complains
builtins.ModuleNotFoundError: No module named 'PRIMA_Base'.

Which makes sense, as I have no local Python package by that name. I tried master (the folder containing my app’s __init__.py, and the name of its containing folder. This is also where I have placed Wing’s project files.

It might also be that my starting directory is incorrect. I have found no documentation stating which directory to start in, so I am starting in master. If that’s not what was intended, I hope someone documents it, or at least drops sufficient hints here.

Changing the starting directory to the parent of the master directory, package name PRIMA_Base errors out as above. So does master. So does the name of the parent directory.

Initial conditions for run_app_via_uplink are really, really under-specified. Any suggestions would be welcome.