I told him I couldn't give him one. But I could give him some overall general advice. Money is made through a series of transactions over a long period of time. There will be both wins and losses. After that I explained why the stock market keeps on going up and down.
Fluctuations occur partly because companies make money, or lose money.
But it is much more involved than that. A stock is only worth what someone will pay for it. Usually, if a company makes a lot of money, its value rises, because people are willing to pay more for a company's stock if the company is doing well. There are also many other factors that affect the value of stocks. One example is interest rates, or the amount of money you have to pay a bank to loan money, or how much it has to pay you to keep your money in their bank.