Most American VCs are looking for a company where there has already been some personal investment on the part of the principals. If there are four or five guys trying to start this company up, they expect you each to invest maybe at least $25,000 of your own money in your company. This means that the company starts off with $100,000 in the principal's own money. This is more than enough to get a lawyer to incorporate you, get patents pending you your intellectual property, get models made, a little proof-of-concept work done, write a business plan, etc.
Often one VC will then step in with a "seed round" which is perhaps $1,000,000. That'll allow the principals to quit their jobs and put them on salary with the new company for at least a year. It'll get you some low-rent office space so you can put your car back in your garage. It'll pay to hire some contractors or consultants to help you flesh out the technical details of your idea. It'll pay for a lawyer to batten down the IP position. And it'll pay to put together the roadshow for the "first round funding."
For example, let's say you have a great idea for a machine that makes peanut butter and jelly sandwiches. You've drawn some sketches and diagrams and flowcharts. You used some of that initial $100,000 to build a prototype that sort of works. And you used some of that $100,000 to get to at least patent-pending on the original aspects of it. With the seed-round money, you'll be able to hire a contract mechanical engineer to refine it and to do all the detailed blue-print drawings that a machine shop needs to really make this thing. You'll be able to afford to hire a contract electrical engineer to design the circuitry to control it just the way you want it. You'll be able to hire a contract software engineer to develop cool, touch-screen user interface for it. You'll be able to pay yourself a full-time salary to really concentrate on it. You'll be able to rent a bay in an industrial park so you'll have the kind of facility you need. You'll be able to buy the materials you need, get the parts made, etc. You'll be able to pay the lawyer to really tighten up those patents and get all the IP in order. And you'll be able to hire a graphics artist to help you put together a really wow presentation.
Your seed VC will then open some doors for you and persuade some other VCs to come to your offices for a day and see your machine and listen to your really wow presentation. Hopefully, three or four of them will decide to buy into your first-round. They may invest $10,000,000 each. Now, you have $50,000,000. You can now hire a real staff, work all of the remaining bugs out of the design, market the product, etc.
If that $50,000,000 starts to run out, you can try for a second round. A third round is even possible.
Eventually, you'll want to do a mezzanine round. This is the money you'll need to build your factory and tool up and actually fill you first orders.
And from here, IPO; you take it public. All that money that comes in from selling the shares then goes back to the VCs... and to the original investors... one of which was you!