Which is an important step in how an electric motor uses magnetic force to produce motion?

Electric motor converts electric energy into mechanical, that is used to do work (that is the motion). The electric motor uses magnetic force to create motion.

Let’s analyze a magnet. If you have two bar magnets with their ends marked "north" and "south", then these will attract each other (opposites attract).

On, the other side, the two other ends (the south end of the first magnet will the north end of the other magnet will also attract each other. These attracting forces create motion - rotational motion.

As the north pole of the electromagnet nears the south pole of the permanent magnet, the current reverses and the poles of the magnets then repel