Merge pull request firebase#232 from hiranya911/master

Updated documentation regarding setting up sample apps

README.md

@@ -4,6 +4,18 @@ A collection of quickstart samples demonstrating the Firebase APIs on Android. F
 
 ## Samples
 
+You can open each of the following samples as an Android Studio project, and run
+them on a mobile device or a virtual device (AVD). When doing so you need to
+add each sample app you wish to try to a Firebase project on the [Firebase
+console](https://console.firebase.google.com). You can add multiple sample apps
+to the same Firebase project. There's no need to create separate projects for
+each app.
+
+To add a sample app to a Firebase project, use the `applicationId` value specified
+in the `app/build.gradle` file of the app as the Android package name. Download
+the generated `google-services.json` file, and copy it to the `app/` directory of
+the sample you wish to run.
+
 - [Admob](admob)
 - [Analytics](analytics)
 - [App-Indexing](app-indexing)