Instead of searching for the one best apple tree in the orchard, you buy a share of the whole orchard. Some tree will dry out, another will give a record harvest — the orchard as a whole usually grows, although there can be several bad years in a row.
A fund that follows the S&P 500 index holds the stocks of the 500 largest US companies. You buy a piece of it like an ordinary stock, and this is the same ownership as in course 1: you can't lose more than you put in, and there is no deadline. Such funds are called ETFs. A good fund charges very little for managing it — tenths or even hundredths of a percent a year.