How does energy get into the apple in the first place?

If we are talking about the apple that fell on the head of Sir Isaac Newton and prompted him to come up with the theory of gravity, then the energy in such an apple is due to its elevation above ground which gives it potential energy and also due to the attraction of the earth. 

Here is a picture  of the net. its 4 squares in a row diagonal and on the third draw one square aove and under