Cross Platform from Win Phone 8 App

Hello, I have a game that’s 40% complete, I made it on windows phone 8 as I have a Lumia for testing and its working very well, but Id like to start getting familiar with seeing it running on different platforms so I can trouble shoot stuff before I get to heavily into the game.

If I have everything running on my windows 8 phone, what do I have to do to get it running on android and IOS, I don’t have either devices to test on and my project folder has entries for these platforms but there is no code.

Any help would be appreciated

Regards
DG