how to store different values of a pot to be called up latter?

Using Arduino Storage
28

I thougth this works just like a pwm output.

This is what a PWM output does.
http://www.thebox.myzen.co.uk/Tutorial/PWM.html

Yes Colin used a digital pot. But note he did that with one pot on one peddle. Using multiple peddle is a bit more problematic
Read what I had to say about it in this thread:-