If you hover over the attribute header in the spreadsheet it will show a note that lists a short description of the attribute, type of value, length of attribute, and an example.

• Boolean - A choice of one or the other typically a Yes (Y) or No (N) option
• String - Free form text field, that allows any valid character up to the maximum number of characters for the attribute
• Integer - A whole number, without a fractional component (1,2,3,etc.)
• Real - All integers and numbers with a fractional component (1, 1.5, etc.)
• Set - A value must be chosen from the set list
• Date - A date formatted as text. The following date formats are allowed: MM/DD/YYYY, M/D/YYYY, MM/DD/YY, M/D/YY,Y YYY-MM-DD

The length for an attribute value is defined: Minimum/ Maximum. If the minimum and maximum are the same value (1/1) it means that the attribute value must be exactly that length.