I have read a lot of blogs and saw many videos but no one explain how to run a Hello world App on a smartphone. Can somebody please help me in running a simple hello world program on android device.
You can read this post: http://www.androidtutorialpoint.com/basics/connect-configure-app-on-real-android-device-and-run-hello-world-program-with-android-studio/
Here everything is explained from how to connect and configure android studio with android real time device (in your case Smartphone) and then run Hello World App. I hope it will resolve your query. All the Best. Happy Coding :)