Easy — you see, you can have your own download of "Big Beyond Belief" all to yourself for 3 entire months (90 days)... and if by that time you aren't consistently and easily putting on slabs of muscle that wreck your wardrobe... then I insist you simply email the manual back. And I'll refund every cent of your purchase price! Just shoot an email to support@ saying "Thanks for letting me try "Big Beyond Belief", but I want a refund". Include your order number (and be sure to email me from the same email address you used to order)... and you will be credited, with a prompt refund.
Unfortunately, there is no way of putting inches on your frame instantly. Growing taller is mostly about genetics. Between 60% and 80% of your height is determined by the DNA that your parents passed down to you, whereas about 20% to 40% of your growth is influenced by your environment. This means your diet, your health, how much you exercise, and how much sleep you get. Until your growth plates (the areas where your bones grow) close, you will keep growing. A good diet, healthy exercise, and lots of sleep can help you get taller in this period than you would otherwise.  For most people, however, growth plates close in their early twenties, and after that, they are not going to gain any inches naturally. Women typically stop growing around age 18 while men may stop around age 20.