Misleading title. This is an explainer on how fonts are encoded and rendered, not a tutorial on how to actually make a font.
Read this instead: https://en.wikipedia.org/wiki/Computers_and_Typesetting
I suspect the URL and the article title are correct, if you buy the whole chapter - and it's just that we are seeing a preview which gets the grounding down first.
If you want a tutorial, http://designwithfontforge.com might be up your alley.