Hi Navaiii,
Yes, first, you'll need to apply to the designated organizations to get the Letter of Support (LOS). Then after you have the letter of support, you can submit your Start-up Visa application to immigration.
List of designated organizations for Start-up Visa
You can find the organizations from the link above and see what they would need from you to apply.
Currently, the start-up Visa processing time is about 32 months. But that doesn't mean that would be the time you will have to wait. I think this is mostly just the backlog, and they are moving faster with applications these days.