Investing in this way is about deciding about future price of given currency. Will rise or fall over the next 60 seconds? If the market behavior will be the same as our prediction we can gain up to 90% of the money that we've invested in option. Otherwise, we lose most or all of the money. It depends on the broker. Here is a simple explained how to invest in the binary options:
http://binaryblog.net/what-are-binary-options/ There is also the opportunity to play for longer time, 60 sec. is the fastest but also the most risky method of earnings.