If you want to have some fun and start diagnosing you should invest in a test light. Go to any of the usuals like Repco, Bursons, Supercheap and they will sell you a really cheap one. I recommend you buy a better quality one personally as it will last pretty much forever and can be used all over the place. Google how to use it from you-tube and then check whether you are getting power to the starter motor when cranking the engine. That will probably point out exactly where your problem is. If in doubt check back here for further help.