[Paper Source] Sheet
You can set the paper type and paper source.
[Select by]/[Paper Source]/[Paper Type]
Specifies the paper to print on by paper source or paper type.
[Feed A5 Vertically]/[Feed A5 Horizontally]
The paper is fed vertically or horizontally when the [General] sheet > [Page Size] > [A5] is set.
[Insert Interleaf Sheets]
Select the type of paper to insert between transparencies when the [Paper Source] sheet > [Paper Type] > [Transparency] is set.
Select [Print on Interleaf Sheets] to print on the inserted paper.
[Use Document Insertion Unit]
Inserts the paper loaded in the Document Insertion Unit as covers or separators.
[Front/Back Cover Settings] 
[Front/Back Cover Settings] Dialog Box
Enables you to insert a cover and back cover. You can select the side to print on and the paper source for each.