The link helps as I was then able to read through the manual. Wow, nice controller. Now to your original question.
The answers are in the manual. Check table in 2. Specifications and Operating Environment
The Pulse input frequency is a minimum of 0Hz up to a maximum of 500Khz. One pulse will step the motor one step and step size is set by the dip switches in Section 6.
Stepper motors are designed for their positioning ability so are normally driven by pulses where one pulse is some set fraction of a rotation or degrees of a rotation or number of steps per one rotation. To stop the motor just stop pulsing (Section 2 spec is 0Hz min frequency).
Section 11 has the timing diagram of the control input signals. The pulse input does not need to be continuous, its just needs to meet the minimum time specs.
So one way to start coding is have an output pin pulse (high, delay, low) each time you press a button (connected to an Axon input pin).
Another is the continuously send pulses when the button is depressed.
You could have another button that increases the rate at which the pulses are send (higher frequency) when the first button is pressed.
Does this help?