All RPi GPIO pins are mapped out in the ‘RPi Pin Out’ area. It’s at the upper-left corner of the board. The user manual has annotated diagrams to show where they are:
http://rayshobby.net/docs/ospi14_manual.pdf
(page 3)
the pin names are not labeled (because there is no space to label them), but you should see the leftmost two pins are marked +5V and 3.3V, so you can use those two pins to figure out the name of the remaining pins.