A VPN introduction about how virtual private networks function, when to use them, what free and open source software is available. Technical language is simple, yet still valuable to users with various backgrounds of computer knowledge. Translated in Chinese.

Print-at-home instructions:

https://www.wikihow.com/Print-Double-Sided

on A4, landscape, fold in the middle. Start stacking bottom to top from the last page of the pdf file.