If you're looking for how to tank pre-BCoB then you just need to find a basic opening rotation guide.
If you're looking in to BCoB you're either ready for it (because you've had practice with things like tanking HM Garuda/Titan) or you got carried/Fate-grinded and need to learn how to use your relic & job skills (Wraith / Inner Beast)
Third option is you won't be ready for when it matters before the way to play the class changes with 2.1