The black screen simply means that there is no launch image set for your app. The newest and in my opinion easiest way to add these is to use an Asset catalog.
If you created your app in a recent version of xCode, an asset catalog named Images.xcassets is automatically created for you.
Navigate to the same by clicking on it and then simply drag and drop your image into the same.
Here's a screenshot:
I would also strongly recommend that you maintain all graphics used in your app via this Asset catalog. The big advantage with using this process is you don't have to worry about the usual naming conventions you would need if you included graphics outside of an asset catalog - for e.g. You no longer have to name retina images as @2x