Now that you have a schedule and faculty, you need to work on curriculum. You are responsible for creating the content shell and assessments, as well as providing a syllabus for the faculty who teach your course. We say "content shell" because for all of the sections you coordinate, there should be some consistency in the semester schedule of what content is covered and when; however, we want the faculty teaching the courses to have autonomy and flexibility as necessary. The content shell can be as detailed as you like, which can be especially helpful to new faculty. With the content shell in hand, faculty can make the course their own and tailor it to their teaching style.
Many gateway courses follow a common syllabus and have standardized their exams. If you create materials and resources for the sections that you teach, we recommend you share those with all faculty who teach the course through a shared resource site such as Box or Canvas. They can pick and choose what works for them, and they can create their own (and hopefully share with all). The key thing to remember is that if you have associate faculty teaching your courses, their primary responsibility is to teach, not to create the content of what they teach!