Cocoapods is required to build this project. First, install pods from terminal.
$ pod install
Then open the .xcworkspace file that is generated by Cocoapods in Xcode.
Since this app is using credentials for an Instagram client that is in Sandbox mode, the client credentials inside of the file /InstagramDemo/InstagramAuthController.swift would have to be changed to use client credentials for an Instagram client that includes your user as a Sandbox User.
When the app is executed, a login prompt for Instagram will automatically open. After getting authorization from Instagram, the app will display a grid view of the current user's most recent photos.