Error building Player: UnityException: Bundle Identifier has not been set up correctly
Please set the Bundle Identifier in the Player Settings. The value must follow the convention ‘com.YourCompanyName.YourProductName’ and can contain alphanumeric characters and underscore.
Each segment must not start with a numeric character or underscore.
Just do what it says.
File> Build Settings>Player Settings
In the Inspector fill in all that infos under the Identification.