I started bowling again last year (similar to you I had bowled jr. high age and only threw straight ball). First thing I did was find some bowling books (got some really good deals on amazon and overstock). Most of the books are dated, but the information on technique are still valid (just ignore the stuff about "new urethane balls"). I bought "Bowling Strikes," "Focused for Bowling," "Winning Bowling," "Bowling 200+," and "Bowling eXecution." I was able to pick each book up for under $10 (shipping included), but maybe you can find them in a library. The information was really helpful to give me an idea of what I needed to do before I was actually bowling, that I watched a friend who has a nice smooth hook and tried to imitate his release.
Also, since nobody has mentioned this yet - It is highly doubtful that you and your friend have the "exact same" span and grip. First things first, you need equipment that is properly fitted for you! Otherwise you risk injury or will pick up bad habits.
Also, concentrate on getting the basic mechanics, don't worry about the hook. I will assume that since you are seeking advice that you want to progress to the best of your abilities - don't worry about hooking the lane. Anybody can pick up a ball, use 2 fingers and crank the h#ll out of the ball and get it to hook. Worry about getting your approach, timing, armswing to an acceptable level. You can buy a "hook in a box," but that won't do you any good if your mechanics are off or you can't hit the same spot on a consistent basis.