Welcome to the board. You'll learn all of what you "NEED" to know and a good bit of what you should know from your Open Water Class.
My only advice to you at this point is to find a good instructor, it will make all the difference in the world when it comes to your first real experience with SCUBA and how safe of a diver you are initially.
There are several threads on here about -how to choose a good instructor- and -what questions to ask potential instructors-
Don't just go with someone b/c of their agency, and don't just go with someone b/c they are the closest. Do a brief "interview" (for lack of a better word) of all the instructors in your area, post a thread in the Canada forum and ask for recommendations of instructors in your area, and go from there.
All instructors are NOT created equally. The rest, you'll learn in class and along the way.