WHAT DOES FLYER PRINTING MEAN?

I just have an issue regarding how to buy on the platform. Exactly what is the measurement of the A5 document (50 percent of the A4) on your platform? I choose to purchase a double sided flyer. I need to confirm that "Whole Colour" to the back side usually means this? Thank you! one SolutionElectronic printing is really a system that allows printin