Temporary HP?

Temporary Hit Points do not stack. But if they are depleted, you can get new Temp HP, yes? But when/how does that happen?

When you take damage, Temp HP is the first to go, correct? 

Example 1: I have 20 Temp HP. I take 20 damage. All 20 of my Temp HP is gone. I am now free to get new Temp HP, yes?

Example 2: I have 20 Temp HP. I take 15 damage. I have 5 Temp HP remaining. If I get +10 Temp HP from a new source, does that restore Temp HP to 15 or replace the Temp HP to 10?

Thanks! 

You can always take new Temp hp, but it never stacks. So if you have 5 Temp hp and get 8 Temp hp you than (can) have 8 temp hp. But you can also decide to stay with the 5 (e.g. when it is from a spell that gives you a bonus when you have that temp hp, which you would loose when taking the 8 temp hp)

Yeah, as Secretfool said.

Just to add a related thread: Temporary hp unstacking