The Course Book as a useful starting point
Communicative Language Teaching required a re-evaluation of the learning processes. A syllabus could no longer be designed as a convenient list of structures or lexical items, but had to now consist of functions and notions.
A course book can be a good source of exploitable and usable material. Activities are sequenced and carefully thought out.
Students will probably expect the teacher to use a course book, so this may be a sensible idea.
A course book provides a useful syllabus for students to follow and a devised course to help them learn.
Material can be reordered, adapted, varied and omitted. Carefully select that which is appropriate for the students. That which is not appropriate should be rejected
https://www.itefli.com/teflblog/using-a-coursebook-in-a-clt-context/