ElvUI PriestAoe is a direct adaptation of Slaren's GridStatusPriestAoe! The main plugin settings are under /ec then go to ElvUI PriestAoe. There you will find all the usual settings for you PoH and CoH.
Note that this only works with ElvUI RAID frames. There is no party frame support, so if you use party frames for your whole raid group then it won't work. The settings for placement of the PoH and CoH icons on your raid frames can be found under /ec -> Unit Frames -> Raid-XX Frames -> (Pull down box) ElvUI Priest Aoe.
You'll need to turn on test mode to see the icons, unfortunately they don't update dynamically yet so just toggle test mode back and forth to redraw the icons! See the pictures below to see how to navigate to the settings. Also note that your raid frames need to be turned on! It does not work unless your raid frames are shown while testing.