I can try to make things a bit more clear, but I'm not sure a tutorial is warranted at this point. There's already docs on building a pyromod, github actions, and docker.
So... this thread is intended for anyone who hosts a mod on GitHub and want a bit of convenience when doing a release. Or this thread is intended for anyone thinking about hosing a mod on GitHub. People who don't use GitHub to mod will have no use for this action and can safely ignore this thread.
The docs for using the Action on the repo README. It assumes the root directory of your mod is in the repo root (e.g., the repo root is where 'mod.json' is located) When the action runs, it will create the mod using the pyrogenesis archive builder as shown here, and output the resulting .pyromod file to $PWD/output. An example is shown on the README on how to access it so it can be used in a separate release action. The release action shown in the example is not required to use the gh-action-build-pyromod action (there are other release actions available on GitHub that can be used instead, if you prefer)
No technical knowledge of Docker is needed to use the Action. I posted this for anyone who is curious about the docker image used "behind-the-scenes" for the action, or for anyone who wants to "audit" how the image is created, or make a PR to improve upon it.
I'd be happy to answer any specific questions related to the Action.
How's that @smiley?