I know a little bit about VC funds because this gets used by startup and early stage biotech/medical companies (I have clients in the biotech area).
There are different types of funding for early stage companies. First, there are angel investors who tend to be high net worth individuals willing to kick in a reasonable amount of capital in select areas of technology. E.g, there was one Australian biotech company that started off with investment from two owners plus an angel (who kicked in around 1 million). Angels invest where they see a quick exit and prospect of high return (ie chuck in some cash in the expectation of IPO within 6 months, hope to at least double their money given the high risk). In the example I mentioned, the angel did double his money in six months when the company listed.
I believe VC funds target a specific sector (e.g., ICT or biotech - biotech/biomedical is the only sector I have any understanding of how this works in) and will raise a fund, for example 200 million, and then make a number of investments in companies over several years. They spread the money over several investments to reduce risk. They also have an exit strategy that is a bit longer term (years instead of months) in order to get their return. There was one VC fund that had a big success recently where they had invested around 10 million in an AU company and sold the company several years later for closer to $100 million. They tend to do some pretty serious due diligence before investing.
I see that FT has just posted a link to a youtube channel that will probably provide useful information, compared to what I have posted here!