An ER diagram is typically built to show the relationships in the tables. If you have those tables, those are what would appear in the ER diagram and be related to each other.

This might help you: http://www1bpt.bridgeport.edu/~jelee/courses/CS450_F09/CPSC450-ExerciseLab1-Supporting-EER.pdf, but really you need to go back and study what an ER diagram is and then how that relates to a real business model.