Good News !
If you have a small business often you do not have a business number as you never registered for HST. You need a BIn to apply for these grants and the option to just register a business number is available and you would not have to register for HST.
We have done this for a few clients recently and it was fairly simple to do. So one should be able to do this themselves.
If you go to the grant link it is there. Go through the questions at https://www.app.grants.gov.on.ca/msrf/#/home
Before you do that, click on these links below, register and get your number
Hope that helps
Where can I find my business number?
The 9-digit business number that identifies your business. This number will be listed on your GST/HST return, employer payroll or T2 corporate tax filing.
If you do not have a CRA Business Number, please apply for one here: Register for a business number or Canada Revenue Agency program accounts - Canada.ca