I think the first place to start are the legal requirements - do you need to be incorporated, have a business number registered for tax purposes etc.
Then you have marketing and communication, websites, etc. Do you need financials as a start up? A business plan for the bank is required etc. I think it all depends on what your business is, where you live and if you're independent vs employed. Hope that helps. I am not a business adviser but that would be my guess. Lesley