Bankers Box® Easylift™ Standard-Duty Storage Boxes with Lift-Off Lids & Built-In Handles - 12" x 12" Letter Size File Storage Boxes for Office, Home Organization & Document Filing

The description of this item is very confusing. It reads as follows: Sheet dimensions: 12" H x 10 W x 12" D.-Overall dimensions: 23" H x 5" W x 25.3" D.What does Sheet dimensions mean? If it is referring to a sheet of paper, which is usually described as L x W (not H x W), and since when does a sheet of paper have a D (Depth)? Also, how will a Sheet of paper that measures 10" Wide fit in a box that is 5" Wide?I want to order this product, but the description is too confusing!