If you go to escape > interface > addons > powerauras > show aura browser, you'll get to see the powerauras UI.
Click on the 'new' button to create a new aura that will pop up. The top part is for animation size, color, texture, etc. The bottom part is for the buff/debuff it should activate on.
Activation: You can find a variety of things it can activate on, the most common one being debuff and buff. I believe that if you have the wrong activation, it will not work. For example, if you'd want a big bomb showing in your screen when an enemy has the 'Spell Reflection' buff on them, that won't work if the activation is set to 'debuff'.
Stacks: Amount of stacks it should have. For example, if you'd want different colors for 2 and 1 stacks of Fingers of Frost, you could make 2 different Auras. One having '=1' and the other '=2'. Then, it'll only activate if it has 1 or 2 stacks respectively.
The field with ??? is the field of the buff/debuff name. It has to be the exact name, but no capitals are necessary if you have Ignore Case selected.
Then you have the area which is for when it should/shouldn't activate. V = Only when x, X = Not when x,
nothing = doesn't matter if you're x or not.
The rest can be ignored, because if you enter all the things above, everything should work correctly.
Lastly, I'll give an example of my 'Lock 'n Load' buff.
Texure: 50
Color: Red
Size: 100%
X,Y: 0, -30
Activation by: Buff - Stacks: >=0 (So the aura will always be active if the buff appears, until it disappears)
Name: Lock and Load (Remember: It has to be the buff/debuff name, not the talent/spell which causes it)
Everything empty besides alive, which is set to 'V'.
Hope I helped ya
