Dry hopping is exactly as it sounds. Once you cool your wort, pitch your yeast and fermentation has taken place (2 wks avg) you add your dry hops to the then beer for a min of 2 wks or as long as you feel needed to have the hops extract a better nose and bitter taste to the beer. If you rack to a secondary you may add your hops then. Be careful if you rack to a secondary though, infection can be an issue if the beer is not topped off to the top of the secondary. I usually just add the dry hops to my primary after a couple of weeks to remove the chance of getting a funky beer.
My question to the poster, is there any special type of yeast used to ferment this brew? I am the biggest fan of Torpedo and if this recipe is cost effective and taste as close to the brew as you say I am sold on brewing nothing else, EVER!