Getting a Social Insurance Number (SIN) in Canada is among the first things you need to do once you land, as you cannot work in Canada without one.
To get your SIN, you need to have a mailing address. The link below takes you directly to the Service Canada website, which tells you how to get your SIN.
The official Canadian Revenue Agency (CRA) website gives information about how your SIN works for taxation purposes.
It is useful to get access to an postal address in Canada to allow you to get your social insurance number arranged as soon as possible after arriving.