You need to be a bit specific: do you have a product idea or a startup idea. They are not the same.
I’m taking a shot in the dark here, but you asked for the process:
- Develop a basic product (aka MVP)
- Test it with your target market
- Review your results
When you are comfortable with your rate of acquiring, keeping and growing customers/users, you have a decision:
Use revenue from customers to organically grow.
Get a bank loan. They will want to know that you can afford to pay back using cashflow, unless you have a clever accountant who can convince them otherwise.
Research types of investors (Angels, VCs, other). Understand how they make money. Start making calls, show up where they are, troll them on social media, etc. Whatever works for you. Explain what exactly you are going to do with their investment capital (product development, talent acquisition, marketing, etc.). Offer what you are willing to exchange for the capital (equity, profit share, friendship, marriage, etc.). Negotiate terms and an exit plan. Don’t sign unless you know the full obligations flowing from the contract.
Review your results. Rinse and repeat.