Start with the honest part
Nobody can guarantee that an AI assistant will mention your business. There is no submission form, no ranking factor to buy, and any agency selling "guaranteed ChatGPT placement" is selling something they cannot deliver.
What can be said with confidence is mechanical: assistants answer from content they can reach and parse. A business that is invisible to an ordinary crawler is invisible to them too.
The fundamentals carry over
Clear pages that state facts plainly, consistent business details, a stable address for each page, structured data that matches what the page visibly says, and genuine third-party corroboration — these are exactly the things modules 2 to 10 asked for.
The practical shift is that assistants extract facts rather than rank documents. Facts stated plainly — "we serve these towns", "we open at 8am", "a callout costs from £X" — are extractable. Facts implied by a photograph are not.
What not to do
Do not invent AI-specific markup; there is no such schema and made-up properties simply make your structured data invalid. Do not stuff pages with question-and-answer text nobody would read aloud. Do not block crawlers you want to be cited by, then wonder why you are not cited.