Writing Curriculum is no different than writing another other large system

Seriously.

So when you develop a large program, be it an operating system, a time keeping system, or any other large piece of software, you are doing the exact sort of thing that you do when you develop the curriculum for a new course.

You have documentation to start with – in the case of a course, the TEKS and the standardized testing that might go with it.  AP Computer Science course description and the AP Computer Science test is one example.

You have an IDE.  In my case, Word and Moodle.

You even get to do some user interfaces, etc.