@rugbygirl - With a mutual fund, the fund invests directly in stocks. Some mutual funds are more or less automatic; they're called index funds and they just try to match a stock index like the Dow Jones. Other mutual fund managers are more activist and they will seek out riskier stocks to try to get a higher return.
That much, I understand, but frankly, even after reading the article I'm not sure I understand what a master fund is! I hope someone else can step in and help us understand the difference. It sounds "bigger" than a mutual fund, like it's maybe for bigger investors! A financial planner or advisor could help, of course. A lot of financial planners are associated with investment banks and naturally want to sell you their own products, but you can also find "fee only" planners who I think charge by the hour and so have no personal stake in what you buy.