For most jobs you need to go through some sort of training. If you want to sell condo listings you will need to take a real estate agent's course and pass a test. In order to be a truck or bus driver you need to obtain a special license. Each province and territory in Canada is responsible for issuing driver's licenses and with that comes some different standards and restrictions. Much like driving a truck you need a license plenty of other professions require one as well. Such as a teaching license, medical license, and even a tax accountant license. Here are the basics that apply to most Canadian regions.
Most provinces have a different classes license for those that want to drive trucks and those that want to drive a bus. There might even be many levels for driving different types of these vehicles. For example, if you're living in condos and are getting an Ontario license than you will need to get an A license to drive a tractor-trailer or towing vehicle that weighs more than 4,600 kilograms. If you're working as a mover taking people to their new home by truck then you also have the option of getting an A license with an R restriction. This allows you to test with a smaller vehicle and just doesn't allow you to drive a truck pulling a double trailer or a trailer with air-brakes.
Those interested in being a bus driver have a number of different categories to choose from in Ontario but usually only one or two in the other provinces. If you want to help people get to their job at as a city bus driver you will need to get a class C license. Those who want to drive regular-sized school buses will need a class B. But, if you get a class B you are also allowed to drive C class vehicles. There is also the option in most provinces to get a different type of license if you are driving smaller buses, limousines, taxis, or ambulances.
If you're looking to get your truck or bus license than you likely can't be taught by someone you know the way that you were when you learned to drive a car. You will likely need to find a school or course to help you learn the basics. When looking for a program you will want to make sure they are ministry approved. Just like you wouldn't just trust anyone with your mortgage, you shouldn't just trust anyone to teach you to drive these huge vehicles. Most drivers' license offices can provide you will a list of accredited schools in your area.