With the online service, it's relatively easy. I would invite you to check it out. You go to the Elections Canada website and check the box for registration services, which will take you to the online service. You will be asked a few questions. If you are registered, you can confirm that you are registered and that it's your correct address. If you have moved recently, you can easily change your address.
If you're registering for the first time—if you've just reached 18, for example, and you want to register for the first time—additional questions will be asked of you, but generally you will be able to register online.
If for whatever reason the online services cannot accommodate your circumstances, you will be guided as to how you can proceed to alternatives to get on the registry.