What is the difference between putting the apostrophe before S and after S??? ‘s vs s’

that is the way of a cheater and cheaters get nothing but bad grades and in trouble.

1.the hosts on two opposing mountains stood,  

2.thick as the foliage of the waving wood;  

3.between them an extensive valley lay,  

4.o'er which the gleaming armour pour'd the day,  

5.when from the camp of the philistine foes,

6. dreadful to view, a mighty warrior rose; in the dire deeds of bleeding battle skill'd,