The book doesn't answer this. Invest 10%, what does it mean? Depends. For most people, this would be in stocks. Since most people don't want to have any effort

The book doesn't answer this. Invest 10%, what does it mean? Depends. For most people, this would be in stocks. Since most people don't want to have any effort with this, it would be an ETF that reflects a broad market index such as MSCI World or Vanguard. Through what? A bank with a broker. Some offer you to save money automatically and invest it into an ETF such as Vanguard.