You better study stepper motor first before you continue with anything.
Relay is not designed for this purpose. This stepper motor step size is 1.8 degree and so it takes 200 steps to make a full 360 rotation. Can you imagine the relay on/off 200 times for one round? And i'm sure the stepper motor will rotate for more than one round. Moreover, you may need to rotate the motor at fast step. So that may yield in 200 times per second or more.
You can use 555 timer to create the pulses but honestly it's not that simple to design the complete working circuit, plus accurate stepping. Using a microcontroller will be a more practical approach. But, of course, it needs pretty much of hard work as well. The simplest way is buy yourself a stepper driver