Keep the template open to your activity
A nine-box structure can hold a compact plan, a set of sketch variations, or a simple handwritten exercise. This version leaves the cells unlabeled so the page does not impose a particular order or subject.
Decide whether the center should act as a main item or whether all nine regions should be treated equally. That decision belongs to your activity; the generator simply provides the consistent divisions.
Prepare content after choosing a final size
The amount of useful space in each box depends on the final print or document dimensions. A layout that holds a short phrase at full-page size may only support a small symbol when reduced.
Choose the destination size before adding detailed content in another application. Keep the square aspect ratio during resizing, and inspect line contrast against the white background at the size where people will read or write on it.