To read further articles about becoming a teacher trainer.
You may find the following useful for further developing your understanding of planning courses.
A Practical Introduction to Teaching Training in ELT (2015) by John Hughes (Pavilion)
Chapter 6 (Managing teacher training) shares practical advice about setting up both in-house and external programmes including handy photocopiable resources for finding out training needs and timetabling input sessions and observations.
Etpedia Teacher Training: 500 ideas for teacher training in English language teaching (2020) by Beth Melia-Leighand Nicholas Northall (Pavilion ELT)
Units 4-6 expand on the ideas in this Unit and include many photocopiable resources for immediate use.
Language Teacher Education (1998) by Jon Roberts (Arnold)
Although a little heavy going, unit 3 analyses different theoretical approaches to designing teacher education courses (or curriculum), unit 4 discusses the pre-conditions at play when designing a pre-service course, while unit 7 focuses on various considerations in designing an in-service teacher training course.
The following research based articles are also useful to develop your understanding of planning courses.