I also live in Ontario and am familiar with the courses.
Calculus, depending on the textbook you are using, will be broken up into a few different parts.
Mainly, it'll involve studying the slope (rate of change) of tangents and secants of functions by means of differentiation and derivation.
First is introductory stuff, reviewing of prerequisite skills (factoring, polynomials, some graphing). After that you'll get into first-principles of deriving functions (finding slope of tangents/secants), limits and continuity of functions. Next you start taking the derivative of functions (slope) using various simpler methods. Then you'll get into implicit differentiation (deriving functions where y is not isolated), related rates and optimization problems (word problems usually having to do with some geometric figure like a cone, cube, sphere, etc). Then you start exponential functions which you will already know, which will lead to logarthmic functions which is a large chunk of the course. Finally is curve sketching which is pretty self explanatory, but lots will be new (finding asymptotes, points of inflection).
Pretty much everything after the first chapter(s) will be new to you, hopefully you'll have a good teacher to guide you through it all. Just do your homework and ask questions and you'll do fine. You already took good initiative to come here!
As for Discrete, I didn't need it for prerequisites so I didn't take it... Even though it would've been smart of me to. But AKG is probably on point with what he mentioned.
If you want to know any more about the Calculus course in detail feel free to ask.