The english speaking person inside the room just manipulates the symbols according to a rule book. It doesn't actually understand the chinese sentences it is producing. So this means a computer only manipulates syntax and don't understand semantics. Therefore computer as manipulators of syntax will never have "consciousness' as humans do.
That is the most important part of the argument. Can computers have consciousness, self awareness and intentionality because that is what is needed for strong AI. The Chinese room argument shows that just because a computer look likes it can think (Turning test) doesn't mean it is.
Good luck on your essay