Recent changes to EU laws require Apple to allow third-party app stores in EU countries. Here's how to use AltStore to sideload iOS apps.

Use File then Open to open up your app, and select the project on the left. Connect your iOS device, then from inside Xcode choose Product, Destination and select your device.

At the end of the download, open the App Store on your iOS device. Make sure you are logged in with the same Apple ID you used to log in to iTunes. Then go to the Updates category, and select ...