First try to get your right result by your own. Like i always say → learning by doing. Your BEST-FRIEND ==> CONSOLE.
Use more the console to inspect the behaviour of your code. What happens at which part of your code? What you will do right now, is called → DEBUGING.
The best way to DEBUG CODE, is to use the CONSOLE.
If you still can’t reach your aim after some sirious tries to debug your code, you can write here again, to get more help.