netnet.studio
As stated in the syllabus, all assignments must be submitted via canvas as GitHub repositories (aka "repos"). You can create these repos using netnet or whichever editor/workflow you prefer.
You can learn more about writing code on netnet.studio on the netnet GitHub wiki, including how to create a "project" (a GitHub repo a netnet). Don't forget that you will need to create a GitHub account first before being able to "log in" via netnet.
other workflows
If you prefer to use your own editor, but you're new to GitHub (or open source development in general) I have a video playlist from a previous class which covers the core concepts as well as a few different local workflows.