Your app's assistant needs access to the material it should answer from. Putting instructions in the builder chat alone is not a permanent knowledge source for people using the finished app.
Start with a small guide
Ask the builder to store your guide in a table with one section per row: a title, topic keywords and the section text. Have the assistant retrieve relevant sections and use them as context when answering a question.
This is a feature to build and test, not an automatic behavior of every AI chat. Ask the assistant to say when the guide does not answer the question rather than inventing a product claim.
Keep access appropriate
Public help text can be readable by everyone. Internal instructions or customer-specific material need server-side access checks. Test with two different users before including private content.
Once the app reads this table, you can update its reference rows without rewriting the assistant's code. Test a question after the update to confirm that the new answer uses the changed material.
Sending relevant sections can reduce unnecessary input compared with sending an entire long guide. AI usage still depends on the model, input and output; there is no fixed saving. Building the feature and running the app's built-in AI use workspace credits.