certainly takes a little skill, I have less than that. (I have an A4 non-duplex printer.)
1) I downloaded the ZIP file from the link
2) I opened the pdf files with nitro reader.
3) from the print menu I printed ‘all odd pages’ (prints come out print side up)
4) taking the stack of printed paper, reversed the order.
5) put the stack print side up into the paper tray.
6) then printed ‘all even pages’.
hey-presto note cards! well they are not perfect. I can’t cut them into A6 because some of the text overruns, so I cut them by hand with scisssors and they are rather odd sizes.. but I’m not complaining they seem pretty succinct notes.
my guess is to do a good job you need to start with the .tex files and use some other tool..