Follow these steps:
- Download and install Xcode 11 Beta (You do NOT need to update your MacOs to Catalina)
- Download the iOS 13 Beta 1 IPSW for your iPhone model from the Internet.
- Connect your iPhone to your computer using a cable
- Open Xcode > create a new project > give the project a name, click ok. When done you should see your iPhone at the top of the Xcode window.
- Go to iTunes, Option + Check for update > browse to the IPSW you downloaded.