Step 1
Brief it once, like you would a copywriter.
Product, angle, audience, and the offer. That is the whole input.
The brief is where you put the things only you know: the angle you want to run, the mechanism behind why the product works, and any proof you can actually stand behind.
Already written the page yourself? Paste it in and the builder switches to typesetting: your words go into the template verbatim, and a coverage check makes sure no paragraph was quietly dropped on the way.