Start with something you know
One scene in the manuscript finds Nathan beside a quiet pier in Marbella, talking into his phone about how he is writing the book. The material begins with his own experiences: work he has done, decisions he has made and things he wants readers to try.
The process develops one chapter at a time through questions, answers, drafting and review. AI helps organise the account. Nathan supplies the experience and decides whether the writing represents it properly.
You do not need to begin with a book
Choose a question your customers ask repeatedly. Explain who the answer is for and why the question matters. Ask AI to interview you one question at a time before drafting.
Include the example you would give in a real conversation. Say where the answer depends on circumstances. If you do not know a fact, mark it for checking.
Read it as yourself
When the draft comes back, check the facts, restore any missing detail and change language you would never use. Keep real examples recognisable and do not let the draft invent a story to make the point sound stronger.
One good article can show a potential customer how you think. It is also a manageable way to learn the process Nathan used for the book.