One benefit of this, apart from creating the necessary add-in that will drive Inventor Server, is that it also generates a helper project (see debugPluginLocally) which enables you to test the add-in locally.
Inside Visual Studio just go to "Tools >> Extensions and Updates..." then search for "Design Automation for Inventor" and click "Download"
Now when creating a new project you'll have the option to select the "Design Automation for Inventor" template
This will create a solution with two projects: one is the actual add-in that you can use with Inventor Server on Forge, the other is the helper project for testing the add-in locally:
Just to show the various parts together. The "Bundle" folder is one level up from the Build Output folder, which is set to "bin\Debug" by default.
All the contents of that folder are then zipped up and placed in the "Output" folder, which will be a subfolder of the Solution's root folder:
In case of using Visual Studio 2019 to create the project leave the option "Place solution and project in the same directory" unticked otherwise the relative path set for "PackagePathname" in "appsettings.json" of the "Interaction" project will not be correct. If you do prefer this option then just modify the value in "appsettings.json" accordingly.