each stage has something to do in each stage, take every step well.
https://dl.google.com/dl/android/studio/install/2.1.2.0/android-studio-ide-143.2915827-mac.dmg
https://dl.google.com/android/android-sdk_r22.6.2-macosx.zip
https://dl.google.com/android/repository/build-tools_r24-macosx.zip