In general, if you want to build a development version of an app for testing purposes, you can do this without having to upload any special resources. The exception to this is when building for iOS, which requires resources for any app build type.
The opposite is also true (with the exception or Windows Phone builds). If you want to build a release version of an App, you will have to upload some special resources.
The required resource for each build type on all platforms are shown here.
Resources can be uploaded using the following developer tools