For the second part of your question about registering for a Business Number, that depends on the structure of your business and a few other factors.
- Are you registering your company with the province you reside in? (or incorporating it).
- Will you have employees? If so you must register for a payroll account.
- As Music Lessons are "exempt" from collecting GST, you would not have to register for a GST account.
Some businesses that hire contractors or subcontractors require them to have a business number.
The following information from CRA explains further about obtaining a business number: CRA Business Number Information
