This are standard newspaper size comic panels.
They are sized to fit for an A4 perfectly. You can print two pages on one piece of paper but you'll have to turn the second page 180 degrees.
If you open them in Photoshop, Photoshop will ask you which page you want to rasterize. Afterwhich, you can draw directly onto the panels with your tablet.
The panels were created in Illustrator. The pages were then saved together with Acrobat.
If you use Illustrator, you can choose to open whatever page you want.
Perfectly fine for commercial use.