In order to create an iOS application, open Xcode and follow the given steps:
- Create a new project or open your already created project (Figure 17):

Figure 17: Xcode project opening/creation
- In our case, we're about to start a new project called firebasecookbook. It's going to be based on the Xcode single-view application project template.
In our application--or when it comes to an example provided in this book regarding Firebase and iOS--we will work with Swift instead. It's just a personal preference, but you can use the one that suits you best.
Figure 18: Xcode project creation
Don't forget to copy that Bundle Identifier ...