As I mentioned above, this incredibly versatile mod can help you out with a lot of tedious or hard to monitor UI elements, but each aura can only track one thing in one way at one time. The mod works like binary, meaning an aura can only be on or off... there's no in between. But what if you want an aura to display under a slightly more complicated set of conditions?
For instance, you may hear from a member of the Hunter class from time to time how clunky Aspect of the Viper is as a mana regeneration mechanic. Often a player will go through several pulls or even entire boss fights not realizing Viper has been left on long past it's usefulness! Unfortunately the only thing PowerAuras will be able to tell you with a single aura is whether the buff is on or not on. It won't tell you when your mana is full and Viper is still on - at least not with one aura!
This kind of complexity can be achieved, however, by linking multiple auras together. Think of each aura as a single condition. In the case of the Hunter's example above there would be a single condition for Aspect of the Viper being on and another condition for your mana level being at or above a certain threshold. By linking these two conditions together you can effectively use a single texture to display only when both of these conditions are met i.e. "Display my aura when Aspect of the Viper is on and my mana is above 90%".
Linking Auras
Since I want to know when the buff is not active the invert checkbox is ticked and this aura is for my second spec so I've unchecked spec 1 down at the bottom of the page.
Next we'll close this aura and return to the main window. Click the copy button and then the character specific page currently highlighted on the top left to paste this aura into the same area. Now that you've copied the aura shift click the original to disable it(More on why we do this later). It's also helpful at this point to make note of the number in brackets in the tooltip for this disabled aura. For my own setup this number is 8.
Now open the newly copied aura (the one that wasn't disabled) so we can change the settings to match up to our second condition. For this example the second condition will be activated by My Spell Cooldown with the activating spell being Bone Shield once again. Make sure to uncheck the Invert box for this aura.
You'll notice in the image to the left there is a highlighted text box. This box is unlabeled in the aura configuration, however on mouseover the tooltip will explain that this box is used to link the aura for multiple conditions.
This is where we'll enter the number of the aura we wish to link it to, in my case the aura number is 8.
That's it!
Now, earlier on we disabled the original aura. We do this because otherwise both auras would be displayed simultaneously. Since we copied the aura in the first place they'd be identical and the aura would simply appear less transparent as it's been doubled up. Disabling the first aura will prevent this from happening. Since the second aura is linked to the first it will not be displayed unless the conditions for both auras have been met.