I'm fairly sure Photrio isn't the best place to look for advice on this.
In Canada, the best advice would be to check the web information provided by the Canada Revenue Agency, and to seek advice from a small business accountant. The telephone assistance offered by the CRA is relatively poor, and they no longer have offices where you can go to ask questions. (If they want to meet with you, they make an appointment with you, and you either meet at your location, or in their secured facilities).
I ran a small, unincorporated photography business for many years in Canada. It had both advantages and disadvantages. I had to register and collect and remit sales taxes, but in some cases (e.g. photofinishing) I was able to buy without paying sales tax. Since then, our version of VAT has come in, so if I was still doing this I would have to register, collect and remit two different taxes (with different rates and rules).
When I was doing this, many of the suppliers would use my tax registration as criteria for offering me "trade" pricing and services. In those days that was a real advantage.
I had to set up and maintain simple business accounting records. And then I had to use those records to fill out the applicable forms when I completed my annual personal income tax return, and either pay income tax on the net income or, in a couple of cases, take the benefit of a small loss to reduce my taxes.
The complexity I always struggled with was how to deal with the purchase of equipment. Technically, when you acquire equipment in a business you are supposed to treat it as a capital asset. You aren't supposed to treat the cost as a deductible expense, but rather you are supposed to amortize that expense over several years. That leads to much more complex accounting records.
One benefit of doing all this extra paperwork is that when you actually organize and track the information, you can learn a lot about your own circumstances

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All of my experiece is, of course, only marginally useful to the OP because of the difference in jurisdictions and the fact that it is somewhat dated.
One thing though - in my jurisdiction, if my marginal tax rate is 40%, than I have fairly high income, and fairly meaningful tax obligations. When that is the case, it is generally money well spent to pay for experienced and informed accounting advice.
Hope this helps a bit.