A pot is a potentiometer . Intended to vary voltage for a number of possible applications .

With these drivers a varying voltage input between 0 and 10 v dc causes a varying output voltage typically from 0 v to 170 volts or so, which will give full motor speed .

Most drives have a 10 v output terminal and a ground terminal across which a 10 kilohm resistor can be connected . A wiper brushing along the length of this resistor will pick up a proportion of this 10 volts from 0v to 10v which is used to feed the input terminal and this is all that a potentiometer does. This in turn causes it to give an output voltage to the motor between a minimum of zero volts which leaves it stationary , to say 170 volts which gives it full chat . This is the simple way to operate and indeed prove one of these drivers. And this is what we are aiming to prove by connecting a pot .

Then In our case we want the computer to send the signal voltage which will vary the motor speed under program control , so the PWM output is used .
This may need to be converted to a 0-10v analog output which many modern breakout boards handle, or I suspect in your case the PWM output may be used to generate a the 0-10v analog input which is needed to control your motor in a separate board . This then replaces the function of the Pot.

A pic of that board would be helpful to try and establish that is correct.