This library simplifies all of this (hopefully), by abstracting away the Broadcom chip details. You only need to refer to the pins as they are on the physical pin layout on the Raspberry PI. For your reference, the pin layout follows. All the pins marked "GPIO" can be used with this library, using pin numbers as below. That gives you several GPIO pins to play with: pins 7, 11, 12, 13, 15, 16, 18 and 22 (with A+ and B+ giving 29, 31, 32, 33, 35, 37, 38 and 40). You should provide these physical pin numbers to this library, and not bother with what they are called internally. Easy-peasy.