The old way of starting an engineering firm
Typical engineers are used to following the "old way" of starting an engineering firm:
Take out a line of credit for about $100k to pay for your upfront expenses, getting quotes for insurance and software, getting purchase orders, executing work, figure out how to submit invoices.
Then, waiting 90 days to get cash (if you got paid), figure out a way to do your projects and continue to sell new ones, execute enough work and start the entire process over when it is time for you to hire help.
Accept the fact that you will not have a decent vacation for 3 years...