it will be easier to help you with the part number for the motor and the circuit or a photo of the reverse side of the "H"bridge
with a quick resistance test you can verify the yellow and maroon wires are the center taps and I expect will both go to terminal 3 in your photo
( I expect you will see the + supply terminal on the left is connected to the centre terminal of the 5 terminals on the right )
as it stands you will have no control of the motor current unless the power supply voltage is the same as that on the lable on the motor
in the past it was normal with simple drivers to have a power supply several times the motor voltage and use high wattage resistors to drop the excess in order to increase maximum possible the motor speed
John