A family of Microsoft word processing software products for creating web, email, and print documents.
@All
This entire series of messages is due to conflicting terminology. This is made evident in the OP's reply dated 11/20.
From the onset the OP has been referring to Booklet layout which has been interpreted by everyone [including myself] to mean Book Fold. In Word these terms are used interchangeably & pertain to a specific feature which prints multiple pages on a single sheet. The final output is then folded to produce a booklet. That incorporates printing on both sides but in a specific order, which is why Two-sided printing is not available for Book Fold documents.
What the OP actually was looking for is how to set up Mirrored Margins [aka, Facing Pages]. This is completely different from Book Fold & is handled in a totally different manner... One primary distinction being that each page typically is printed on separate full-size sheets which are to be bound rather than being folded. IOW, a book not a booklet. Also, Mirrored Margins allows for - but doesn't require - Two-sided printing. That's why the replies he received did not provide the desired result & that Two-sided printing is available for his other documents.