Electrical Engineer Arduino Project

I need help with an Arduino project.
I need a motor to go back and forth over a given distance using some proximity switches.
A project like this already exists see attached video, but I am having a hard time recreating it.

----------

I need help configuring this project.

The motor should go a certain distance given a speed analogue.
Then hit a proximity switch in which case the motor changes direction with a given speed analog.
This process will repeat forever.