Before you can start working in Canada you have to get your Social Insurance Number or SIN. Social Insurance Number in Canada is similar to SNILS in Russia and Social Security Number in the United States.
Luckily, this post is short due to a simple procedure of obtaining SIN in Canada. What you need to do is to find the closest office of Service Canada and come to it personally with your Passport and Work Permit. It should be possible to do everything by mail, but I don’t really think it worth trying it.
Once inside you tell a person who is serving that you are looking for a SIN. Everything else is pretty straightforward: they ask you a few questions including your current address and then they produce a piece of paper with a 9 digit number on it. It’s your SIN.
What you should keep in your mind though is that while SIN is produced instantaneously, a plastic card with this number will be mailed to the address you’ve provided. So you would be better to find your new home first…