Hi @abertaud,
You can place your content anywhere on the canvas, as long as it’s within the bounds.
The canvas itself represents your tracking image (visible in the background), and how your content will be positioned relative to it.
In instances where a tracking image hasn’t been set, the experience’s zapcode will be displayed in the canvas’ background. You will still be able to position content on your canvas. Without a tracking image however, your content will be displayed relative to the zapcode itself when scanned through the Zappar app.
Hope this helps. If you’re having any other issues with Designer please let us know
All the best,
Seb