This is the sample app from the iOS app used in the Getting Started article.
You can find additional reference documentation here:
Before building in Xcode, you will need to use Carthage
to install the iOS SDK.
Carthage is a decentralized dependency manager that builds your dependencies and provides you with binary frameworks.
You can install Carthage with Homebrew using the following command:
$ brew update
$ brew install carthage
Run carthage update
to install dependencies.
If you are using Xcode 12, please see the workaround from carthage