That sounds like a sales pitch if I ever heard one. It isn't hard to do, I have done several with no problems. The best advice is to go to home depot or lowes and buy a book on how to do it as well as putting in some research on the internet. You will find everything you need to know
First off you will need to get a blue print from a qualified source. You will need to get a building permit and it will have to be approved and inspected before and after you build your roof! If you have not done this type of building before , you might want to consider getting some quotes from qualified contractors. Bad construction means water leaks and ruined roof. I built houses for over 15 years this is a job for a professional contractor. If you still want to do this after reading this you can go to the contractors desk @ home depot or lowes and they can point you in the right direction. Cutting rafters and ceiling joists is no easy feat for an trainee.