How to Print a Booklet with InDesign
A booklet means that both sides of each page are printed, and typically, there are two pages on each sheet of paper, as seen in saddle-stitch brochures, which are folded and stapled on the fold.

1
Your InDesign document
The number of pages of your document must be divisible by 4. Then go to -> file -> Print Booklet.
2
Setup of the booklet
Select 2-up Saddle Stitch. Then go to Print Settings
3
Configure the printer
Select the printer you want your booklet to be printed on. Then be sure to check the box -> Print Blank Pages.
4
Setup the format
Pick your paper size and orientation. Then adjust the scale as you wish. Be sure to select -> Page Position -> Centred. So your double side's will match. Once done, you can go to -> Printer and make your booklet ready for printing.