When I grew up I was told, "build a better mouse trap, and the world will beat a path to your door". I grew up with this assuming this was the case, and of course it's not that simple.
It's very rare that an investor will give you money unless you can demonstrate beyond their doubt that you can make money with the idea and that the idea will make enough money to give the investor a healthy return on their investment. They aren't in it to just give you money.
Different investors have different experiences and different levels of doubt, so you will have to overcome all that doubt of any potential investor before they will give you money. These days, investors really need to see some kind of revenue generation, that means you have solve issues around market penetration and actually prove that you can make money with whatever it is you are selling. That's more than just customers, revenue must exceed all expenses by a wide margin so that you can not only sustain your business but grow it too.
I remember in the dotCom boom, companies where making money based purely on investors, that had no sustainable income. We're all still paying for that; and investors are a lot smarter now. A good song sounds nice, where is the proof?
Business Plans will help you organize your thoughts around how to do it, but you'll still need to execute. An investor won't give you a dime with just a business plan; unless you have a reputation to back your ideas. You have to make the plan, then execute the plan and prove your planning skills and adaptation skills will still make money.
My advice would be to ask questions, "how can I do this if there were no grants or investors? Could I demonstrate the need for my product or service in a small way that would make a customers want to buy?"
Of course the fundamental problem you have to ask yourself is, "what pain am I solving that people are willing to pay you their hard earned money to solve?" If you cannot answer that one, you won't go very far.