need very basic sample application and steps to run the application in unity.

well you'l want to learn unity, its not just for games. Its going to be the easiest way for you to get into creating an application for the go. Just decompiling other people's APK's isnt going to get you anywhere. 
I'd recommend you get unity, download the oculus samples from the asset store, try building those to the go and see how that works.