How to play Tank as DK

Since i obviously suck at pvp & pve, i figured since i cant dish it out, i might as well be able to take it. So i choose tank as my secondary specialization. But i know diddly squat about tanking. What abilities are important, what, where & when to use them? Can someone guide me? Please suggest some macros as well. One more thing, what are glyphs and how to get them? Im currently lvl 79

Ill help you out,

Go to your browser, type google and set that as homepage, in google search you type "MoP DK tank guide" and you'll find something like this:

https://www.youtube.com/watch?v=KQuNPOc4Mng