If you for any reason don't want to fully populate your headers, use jumpers to short 1A to 1B and 2A to 2B where you have any motors missing. Keep in mind that, to have the motors work, you must have all the motors connected, otherwise the circuit is interrupted. To map the picture to the diagram, left is top, two wires are connected on the left side and two on the right. See the picture of my distribution board with two Y motors and four Z motors, each set wired in series. On the last header, connect 1B and 2B pins to the 1B and 2B wires going to the driver. Continue this A to B connection as you add more headers. Connect 2B from the first header to 2A on the second header. Connect 1B from the first header to the 1A on the second header (i.e., the header where you'll plug in the second motor).
#Gecko driver board driver
To wire the motors in series, split the 1A and 2A wires from 1B and 2B wires in the cable coming from the driver and connect to the first and third pin on the header where you'll plug in the first motor.
#Gecko driver board series
In my case, the same four motors wired in series had no problem lifting the same gantry with power to spare. Given how little voltage each motor really needs, you should be able to get five times the power if you use five motors.
#Gecko driver board full
In contrast, wiring the motors in series splits the voltage, but every motor gets the full current. I found this out the hard way, when I was building a printer where I used four motors to lift a fairly substantial gantry in the vertical direction. If you wire the motors in parallel, every motor gets the full voltage, but the current is split, meaning that the total current is still only 2A - no matter how many motors you add, there is no more power. Pololu Shield is rated 2A and gets 12V from the RAMPS board (or at least I think it does). Using Ohm's Law, such a motor needs 2.2V of power. RepRap motors are often rated 2A and 1.1ohms. To see why, consider the electrical characteristics of the motors and the driver. Either will work, but motors wired in series will produce more power. To connect multiple motors to a single driver, you can wire them either in parallel, or in series. The wires are connected in order 1A, 1B, 2A, 2B. Each circuit has two wires, call them A and B. Each motor is driven via two circuits, call them 1 and 2.