add more instructions to README

README.md

+# react-native-threads
 
-# react-native-thread
+Spawn new react native JavaScript processes for CPU intensive work outside of your
+main UI JavaScript process.
+
+Despite this package's name, this isn't real 'threading', but rather multi-processing.
+The main tradeoff of using this library is memory usage, as creating new JS processes
+can have significant overhead.  Be sure to benchmark your app's memory usage and other
+resources before using this library! Alternative solutions include using `runAfterInteractions`
+or the [Interaction Manager](https://facebook.github.io/react-native/docs/interactionmanager.html),
+and I recommend you investigate those thoroughly before using this library.
 
 ## Getting started
 
@@ -9,6 +18,28 @@
 
 `$ react-native link react-native-thread`
 
+### Android
+
+For android you will need to make a slight modification to your `MainApplication.java`
+file.  In the `getPackages` method pass in `mReactNativeHost` to the `RNThreadPackage`
+constructor:
+
+```java
+    @Override
+    protected List<ReactPackage> getPackages() {
+      return Arrays.<ReactPackage>asList(
+        new MainReactPackage(),
+        new RNThreadPackage(mReactNativeHost)  // <-- Here
+      );
+    }
+```
+
+Also note that only the official react native modules are available from your
+threads (vibration, fetch, etc...). To include additional native modules in your
+threads, pass them into the `RNThreadPackage` constructor after the `mReactNativeHost`
+like this:
+`new RNThreadPackage(mReactNativeHost, new ExampleNativePackage(), new SQLitePackage())`
+
 ### Manual installation
 
 
@@ -23,7 +54,13 @@
 
 1. Open up `android/app/src/main/java/[...]/MainActivity.java`
   - Add `import com.reactlibrary.RNThreadPackage;` to the imports at the top of the file
-  - Add `new RNThreadPackage()` to the list returned by the `getPackages()` method
+  - Add `new RNThreadPackage(mReactNativeHost)` to the list returned by the `getPackages()` method
+  - Also note that only the official react native modules are available from your
+    threads (vibration, fetch, etc...). To include additional native modules in your
+    threads, pass them into the `RNThreadPackage` constructor after the `mReactNativeHost`
+    like this:
+    `new RNThreadPackage(mReactNativeHost, new ExampleNativePackage(), new SQLitePackage())`
+
 2. Append the following lines to `android/settings.gradle`:
   	```
   	include ':react-native-thread'
@@ -35,6 +72,8 @@
   	```
 
 #### Windows
+Windows support is not yet implemented, but PRs are welcome if you want to give it a shot!
+
 [Read it! :D](https://github.com/ReactWindows/react-native)
 
 1. In Visual Studio add the `RNThread.sln` in `node_modules/react-native-thread/windows/RNThread.sln` folder to their solution, reference from their app.
@@ -44,10 +83,50 @@
 
 
 ## Usage
+
+In your application code (react components, etc.):
+
+```javascript
+import { Thread } from 'react-native-threads';
+
+// start a new react native JS process
+const thread = new Thread('path/to/thread.js');
+
+// send a message, strings only
+thread.postMessage('hello');
+
+// listen for messages
+thread.onMessage = (message) => console.log(message);
+
+// stop the JS process
+thread.terminate();
+```
+
+In your thread code (dedicated file such as `thread.js`):
 ```javascript
-import RNThread from 'react-native-thread';
+import { self } from 'react-native-threads';
 
-// TODO: What to do with the module?
-RNThread;
+// listen for messages
+self.onmessage = (message) => {
+}
+
+// send a message, strings only
+self.postMessage('hello');
 ```
 
+Check out the examples directory in this repo for demos of using `react-native-thread`
+in a functioning app!
+
+### Thread Lifecycle
+
+- Threads are paused when the app enters in the background
+- Threads are resumed once the app is running in the foreground
+- During development, when you reload the main JS bundle (shake device -> `Reload`) the threads are killed
+
+### Debugging
+
+Instantiating Threads creates multiple react native JS processes and can make debugging
+remotely behave unpredictably. I recommend using a third party debugging tool like
+[Reactotron](https://github.com/infinitered/reactotron) to aid with this. Each process,
+including your main application as well as your thread code can connect to Reactotron
+and log debugging messages.