Explaining "ground" and grounding as simple as possible
There is a lot of history in the electrical/electronic term ground.  Since you are just starting out, think of it as the reference that all voltages are measured with respect to.  Look at this circuit;



You could call the node top, bottom, or middle ground.  The circuit will work exactly the same.  If you call bottom ground, all the voltages will be positive.  If you call top ground, all the voltages will be negative.  The voltage across each resistor will, however, not change in polarity or value.  It is just a reference.