Normally, wiring stepper motor is easy with schematic wiring diagram. Two-phase stepper motors can have 4, 6 and 8 wire termination types (not including any encoder wiring). Some stepper motors also offer 8 leads, allowing for a variety of wiring options, depending on the speed or torque requirements of the stepper motor.
The 8 wire stepper motor can be connected in series or in parallel with the windings. However, wiring stepper motor without a diagram will take more time. You need to resolve which coil pairs are "identical." Two pairs are basically the same. You want to connect the two pairs in series so that you basically have only two coils, each twice the length of the coil. Polarity is important, therefore, you also need to connect them so that the two coils "add" to each other. You can choose two coils at random, insert them and see if they work. If the stepper motor rotates, you have two coils that are not two halves of the same coil. You can then "add" other coils at once, experimenting with different configurations and polarities, until you can identify which two coils to connect to and which direction to connect them to.