Xcode 8: how to change targeted device family

I developed an app for iOS 9/10 for iphone devices but my client would like to present and show it first running on an iPAD (always iOS 9/10). I have tried to compile and run it on my iPAD mini but the result is awful. I mean that the visible screen is much smaller than the one of the iPAD and moreover it is very slow and the graphics is busted. This is strange because I wrote many constraints and my app shows good on every kind of iphone (> 4S). Moreover the app completely crashes when I tap on a table cell row to show the second View Controller... Why do I see this on ipad? Shall I change the device target which at the beginning was set to iphone only? In Xcode 8, under project --> Build Settings --> Targeted Device Family I see 3 options: 1, 2 and 1,2. What do they mean?

How do I change my build settings in Xcode?

Choose the project in the Project Navigator on the left. Select the Configurations target from the Targets section and click the Build Settings tab at the top. The Build Settings tab shows the build settings for the Configurations target. It's possible to expand this list with build settings that you define.

iPhone/iPod touch is 1, iPad is 2, and universal (iPhone and iPad) is 1,2.