I know a lot about this beer
its basically a generic pale ale recipe, not like sierra nevada pale ale, very light on the hops, and they actually use apricot flavoring, not puree, when they brew this beer, similar to the blueberry wheats and raspberry wheats and stuff like that
What I would do is ferment the beer until day 5 or so, using a regular california ale style yeast, then throw it into a secondary fermenter, add your puree, or even juice, and bottle it accordingly
if you had actual flavoring, which you can get at a homebrew store, you can make the pale ale and when you go to bottle/keg, throw in the flavoring right into your bottling bucket, rack the beer on top of that, and then into your bottles, if you are kegging, add it to the keg, and throw your beer on top of it then carb
As for the exact amount of flavorings per what I am assuming is a 5 gallon batch, i couldnt tell you as I have never used it before, so its kind of up to your tastebuds as far as whether its going to be too much or too little