You should have the thorough subject matter knowledge.
Subject is related to mobility testing. Userability and many more things goes inside.
you need to make a course material on ebook
ebook should start nicely from introduction and preface and content list divided into topics and chapters ...
The flow of each chapter should be practical
Each chapter should have related knowledge. No bitting around bush. complete knowledge to be driven in normal words.
Book should be enough about 30 pages.. Internal practical diagrams or images to be done by you to explain in practicality.
no english errors, no copy paste work, no plagiarism.
Also, you need to make a nice case study based on your experience and put it there.
This material is required to training purpose. So target audience is learning. So content should be such that it teaches rather sales, and case study should help them follow and do the things in practical and learn.