All of those tags have already been converted (or close to them) on
this thread over at wowace.
The Events list at the bottom sets up what "events" your LuaText listens to. If you're doing an HP text, then you need to tell it to listen to the health-related events (this tells it that your HP changed). If you're doing a Power text, then you need to listen to all the Power events (mana, rage, energy, runicpower, etc) that your text is going to deal with.
Every time there's a change, WoW sends an "event" to your computer - this tells what changed, on whom, and how. So to deal with changing HP levels in combat, you need to listen to those events that have to deal with HP, etc, etc.