yanlantao on "first checkout, the project doesn't build"

I check out the latest IOS WordPress from Git. When I try to run the simulator, it gives three build errors as following. I will really appreciate it if anybody could answer it. my environment OS X El Capitan + Xcode 7.2 beta

-1- Diff: /../Podfile.lock: No such file or directory
-2- Diff: /Manifest.lock: No such file or directory
-2- the sandbox is not in sync with the Podfile.lock. Run 'pod install' or update your CocoaPods installation.