The flashcards in your PDF file are already pre-arranged for double-side printing, either by hand (A) or for printing with a duplex capable printer (B).
For manual double-sided printing, you’ll print the odd pages (question sides) first, then put the paper back into the printer and print the even pages (the answer sides).
Note: Depending on your printer you may have to flip or turn the stack of paper. Before you print a complete deck of cards, try printing only the first 4 pages so that you can test which way you have to put the paper back into your printer.
Depending on your printer, you now can activate duplex or two-sided printing in the print options. For some printer models, you can do this by selecting the Output Settings menu and set “Two-sided Printing” to “Yes”.
Other models might have a separate “Duplex Printing” menu in the print options.
Instead of printing the cards you can also study them on your Mac or iPhone with the Flashcard Hero app. You can find instructions how to study the cards here.