How to build a new PDF from scratch

1. Pick a build mode

   "Build mode" radio chooses Online canvas (default — a blank A4 you decorate visually) or Plain text → PDF (typed text becomes a multi-page A4 with wrapping).

2. Use the matching surface

   Canvas mode: drop text and image overlays on the studio above (it writes the internal visualEditsJson). Plain mode: type or paste into "Document text" — content is ignored in visual mode.

3. Press Run

   Canvas mode needs at least one overlay or a page-removal entry, or it errors out. Plain mode needs non-blank, non-junk content (passes a substantive-text check) — empty or whitespace-only input errors out.

4. Download the PDF

   Output is base64 PDF saved as built-visual.pdf (canvas) or built.pdf (plain). For long text-only documents prefer Plain mode; for posters / flyers / one-pagers, Canvas mode.