elaborations (#2111)

added some elaborations to make it easier for developers with no ios experience.

docs/installation-ios.md

@@ -10,8 +10,13 @@
 
 2. In Xcode, in Project Navigator (left pane), right-click on the `Libraries` > `Add files to [project name]`. Add `./node_modules/react-native-navigation/ios/ReactNativeNavigation.xcodeproj` ([screenshots](https://facebook.github.io/react-native/docs/linking-libraries-ios.html#step-1))
 
-3. In Xcode, in Project Navigator (left pane), click on your project (top) and select the `Build Phases` tab (right pane). In the `Link Binary With Libraries` section add `libReactNativeNavigation.a` ([screenshots](https://facebook.github.io/react-native/docs/linking-libraries-ios.html#step-2))
+3. In Xcode, in Project Navigator (left pane), click on your project (top), then click on your *target* row (on the "project and targets list", which is on the left column of the right pane) and select the `Build Phases` tab (right pane). In the `Link Binary With Libraries` section add `libReactNativeNavigation.a` ([screenshots](https://facebook.github.io/react-native/docs/linking-libraries-ios.html#step-2))
 
-4. In Xcode, in Project Navigator (left pane), click on your project (top) and select the `Build Settings` tab (right pane). In the `Header Search Paths` section add `$(SRCROOT)/../node_modules/react-native-navigation/ios`. Make sure on the right to mark this new path `recursive` ([screenshots](https://facebook.github.io/react-native/docs/linking-libraries-ios.html#step-3))
+4. In Xcode, in Project Navigator (left pane), click on your project (top), then click on your *project* row (on the "project and targets list") and select the `Build Settings` tab (right pane). In the `Header Search Paths` section add `$(SRCROOT)/../node_modules/react-native-navigation/ios`. Make sure on the right to mark this new path `recursive` ([screenshots](https://facebook.github.io/react-native/docs/linking-libraries-ios.html#step-3))
 
-5. In Xcode, under your project files, modify `AppDelegate.m` according to this [example](https://github.com/wix/react-native-navigation/blob/master/example/ios/example/AppDelegate.m)
+5. In Xcode, you will need to edit this file: `AppDelegate.m`. 
+This function:
+````````
+- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions { ... }
+````````
+is the main entry point for your app. Its content must be replaced with the content of this [reference](https://github.com/wix/react-native-navigation/blob/master/example/ios/example/AppDelegate.m)