I am using the Pololu A4988 stepper drivers. That web page has a lot of useful information including a wiring diagram.
I wrote my Simple Stepper Program Thread for people who already have a basic understanding of stepper motors. Wikipedia has a good info.
By the way I have just realized that instead of 2 separate programs in that Thread I had repeated the first program (nobody seems to have noticed). I have now corrected that and I hope that has not been the cause of your confusion. Feel free to slap my wrist.
I don't think I can provide a teaching-from-nothing introduction. In any case it would just be duplicating info that is widely available elsewhere.
I wrote my demo code with what I hope are meaningful names for variables rather than comments. I hope they make sense for someone who already knows the general concept of stepper motors.
Writing in the Forum is necessarily different from a face-to-face experience where either or us can instantly interrupt the other if we don't understand something.
If you want to point out specific items in my code I will be happy to try to explain further.
...R