Have you tried first searching these forums and google?
Everything you need to know is either on here, or on the health canada website.
When you match to residency in the US, you have to immediately get all your paperwork done for health canada to get a SON(Statement of Need), and when(or if) you get it, then you are on the way to getting the J1 visa. The SON is a pre-requisite for getting your J1 visa. Once you secure the SON, the J1 process should be pretty straightforward.
This is assuming of course you are 1) Matched to a US residency 2) Are a canadian citizen/PR looking for a J1 Visa.
No one can provide you a timeline that is 100% accurate, as with everything regarding immigration its an individualized process...but you should be able to find a rough timeline and steps online.
EDIT:
It looks like you are actually a matched m4 medical student based on your post history - to Internal Medicine.
You need to IMMEDIATELY GET ON THE PROCESS FOR SUBMITTING THE SON paperwork.
The fact that you didn't already know about all of this, yet somehow matched, is beyond amazing(in a very bad way) to me.
Go on facebook, if you don't have a facebook make one, and go join the page "Canadian Student Association @ SGU" they have a bunch of useful links to get through the process.
How have you not been told by your school about this already? You are already 3 days behind everyone else who submitted their paperwork on friday.
I pray for you that it works out and you see this message and go sort it out ASAP. Literally every minute you waste not submitting your SON application - the riskier it gets that you might not EVEN GET A SON.