Bipolar stepper motors usually have 4 wires. That’s two wires per coil, hence the name Bi-Polar. Below are schematics of setups used with stepper motors.
Steppers motor wires are usually labeled as A, B, C, D. A and C are connected, as well as B and D. You can generally determine which wires are connected using a multimeter,measuring the resistance of two wires at a time. If you measure a small resistance (1-30 ohm) then they are connected.
It does not really matter which set of wires are AC and BD as the only differences will be the direction the motor travels. The direction is usually controlled by the stepper motor controller making it easy to change.