When you get off the plane in either Calgary or Toronto (it must be one of these places), make sure you have all your paperwork at hand to show immigration (this will be everything that was sent to you from the Canadian Embassy). The immigration officer will process your information and give you your work permit (this is limited to exactly what the permit allows you; most are tired to the company you have accepted employment from). Once you reach your destination, your next move is to get a social security number (there is a Service Canada office in Saskatoon; it is the UK equivalent of your National Insurance number, you cannot work unless you have this). Once you have these, you are set to start work.
For most people, a car is an essential item and in Canada, it’s a must due to the cold climate. Buying a car can be a mine field in any country let alone a country you have only been in a few hours. You have two options, buy a car outright with the money you have bought with you or try and get credit. There are places that will give you credit on a car but you will need to put some kind of deposit down, they normally like 25%. I would recommend that you pay cash for your first car in case you decide to return to the UK, you don’t want to be paying for a car you can’t drive.