How to draw the graph of y = sin(x + pi/4) and y = sin(x - pi/2)

This lesson shows how to draw the graph of y = sin(x + pi/4) and y = sin(x - pi/2). Reader need to understand how to draw the graph of y = sin(x). In which case should shift the graph of y = sin(x) left certain units and in which case should shift the graph of y = sin(x) right certain units. Understand the standard sine function y = A sin(Bx + C). What does these parameter A, B and C represent.