Connect this positive protrusion to the negative flat spot with a metal wire. When you do this, electricity flows through the metal wire.
However, just connecting the metal wire does not generate the power to move the object. The battery and the metal wire will gradually become hot. This is because there is energy in the electricity that flows. It is this energy that makes things hot.
The motor extracts this electrical energy and converts it into the power to move things. In other words, batteries can turn motors because they can create electrical energy.