Stepper Motor

Machine: _Stepper motor

Board: _

Firmware: _

Problem/ Question: _I have nema stepper motor with 4 wire color red,blue,green&black - i want to run a stepper motor - so i have connected red and blue wire to positive terminal of 12v(can go upto 24v) power supply and green and black wire to negative terminal of power supply but stepper motor is not rotating - even i have checked voltage using multimeter in the motor pin. please help me to fix this issue.