A more realistic path than the Club Card walkthrough: find a project close to what you need, download it, put your own logo and business name on it, then print. This walkthrough uses a generic Invoice project, but the same steps apply to anything in the Project Library.
1. Find one
Browse the Project Library for something close to what you need - a
generic Invoice, for this walkthrough - and download its .yatate file.

2. Open it
Use Open File from the Main Menu and pick the
.yatate file you downloaded - it opens straight into its form.
(screenshot pending - retake against the current Open File flow)
3. Open Project Editor
Instead of filling it out, use the Main Menu's Edit item to land on Project Editor - the hub for every file that makes up the project.

4. Customize the header
Tap the overlay file that holds the header (commonly overlay.json) to open the
Overlay Editor:
- Select the header image block and replace its source with your own logo.
- Select the header text block and edit it to your business name.
- Save.

5. Fill it out
The app bar's Open Project button returns to Input Form for the same document - fill in an invoice.

6. Generate, then print or save
Tap Submit. Once it passes validation, you land on the PDF Preview, now showing your own branding - Print sends it straight to a printer, Save keeps a copy (PDF or PNG) on disk.

The customization you just did lives in the project's own files, not in the app - open Project Editor any time to keep refining it, or see Docs for everything past the basics.