After see make: magazine's Joule Thief I want to "make: a toroid transformer":D. Does anyone know any link to a comprehensive explanation on transformer calculations(like turns of primary, or secondary coil for upping or downing voltage/amperage)? I think some the the variables are primary wire turns, primary voltage, primary amperes, secondary wire turns, and secondary resistance load?

It's basically (ignoring coupling issues) the ratio of the turns. Think of it as a gear box for electricity. So if you have 10 turns on the primary, and 100 on the secondary, your current will decrease 10x and your voltage will increase 10x.