What must happen to the electrons in a material to create an electric current?

You have to have electrons that are in the materials conduction band. Then you apply a voltage across the material. 

For the electrons in a material to create an electric current THERE MUST BE FLOW OF THE ELECTRONS, CHARGES MUST FLOW CONTINUOUSLY FROM ONE POINT TO ANOTHER.Electric current refers to the continuous flow of electric charges through a material. For an electrons to flow in a material, the material must be a conductor.

Amethod of procedure that has characterized natural science since the 17th century, consisting in systematic observation, measurement, and experiment, and the formulation, testing, and modification of hypotheses.