As soon as you get your subwoofer, we (at least HD and I so far
) will help you read the manual. You don't need to print all the pages either, just a couple pages that you need to do your specific connections should suffice. If you have a smart phone, then its easy, obviously.
What kind of sub you have in mind? If you feel your towers are so capable already, you may want to consider subs that can go an octave or two lower than your towers.