clarify build instructions

// FREEBIE

BUILDING.md

@@ -4,17 +4,18 @@
 
 Clone the repo to a working directory
 
-## 2. Depenencies
+## 2. Dependencies
-
-### tldr;
-
-Build and configure dependencies.
 
+To build and configure the libraries Signal uses, just run:
 
 ```
 make dependencies
 ```
 
+If the above fails to run, or you just want to know more about our
+dependency management systems, read the next section, Dependency Details.
+Else if the above completed without error - jump ahead to step 3.
+
 ### Dependency Details
 
 We have a couple of dependency management tools. We us Carthage for
@@ -35,7 +36,7 @@ pod repo update
 pod install
 ```
 
-occasionally, CocoaPods itself will need to be updated. Do this with
+Occasionally, CocoaPods itself will need to be updated. Do this with
 
 ```
 gem update cocoapods
@@ -55,6 +56,12 @@ git submodule update --init
 carthage build --platform iOS
 ```
 
+### Building WebRTC
+
+A prebuilt version of WebRTC.framework resides in our Carthage submodule
+and should be installed by the above steps.  However, if you'd like to
+build it from source, see: https://github.com/WhisperSystems/signal-webrtc-ios
+
 ## 3. XCode
 
 Open the `Signal.xcworkspace` in Xcode.
@@ -64,24 +71,18 @@ open Signal.xcworkspace
 ```
 
 In the Signal target on the General tab, change the Team drop down to
-your own. On the Capabilities tab turn off Push Notifications and Data
+your own. You will need an Apple Developer account for that. On the
-Protection. Only Background Modes should remain on.
+Capabilities tab turn off Push Notifications and Data Protection. Only
-
+Background Modes should remain on.
-Some of our build scripts, like running tests, expect your Derived
-Data directory to be `$(PROJECT_DIR)/build`. In Xcode, go to `Preferences-> Locations`,
-and set the "Derived Data" dropdown to "Relative" and the text field
-value to "build".
 
 Build and Run and you are ready to go!
 
 ## Known issues
 
-Features related to push notifications are known to be not working for third-party contributors since Apple's Push Notification service pushs will only work with Open Whisper Systems production code signing certificate.
+Features related to push notifications are known to be not working for
+third-party contributors since Apple's Push Notification service pushes
+will only work with Open Whisper Systems production code signing
+certificate.
 
 If you have any other issues, please ask on the [community forum](https://whispersystems.discoursehosting.net/).
 
-### Building WebRTC
-
-A prebuilt version of WebRTC.framework resides in our Carthage submodule (see above).
-However, if you'd like to build it from source, see https://github.com/WhisperSystems/signal-webrtc-ios
-