How can you recognize a Hybrid app on android using Appium?

I would like to launch a hybrid app (.apk file) on my android phone. I am using TestNG and Java. I would like to see a java program that actually does this. More specificall, How does the app get recognized, before it gets launched? If the user is on some screen and the app is located on some other screen does it still get launched? How do I do it? I am using an Android phone having 4.4.4. Appium (1.4.1 ) client runs on Windows 7.