You need CocoaPods (https://cocoapods.org/) to handle dependencies, so if it's not installed yet you should run the following command:
$ sudo gem install cocoapods
Then move to the project's directory and run:
$ pod install
This will download all the dependencies for the Xcode project and will create a new file named Vloom.xcworkspace. You should use that file to open the Xcode project and run the app.