How Object tracking is done in Arkit-2 using Unity?

Hi I was trying to Augment on Objects using Arkit 2 Object tracking.I opened the UnityARObjectAnchor.unity scene.Arkit2 contains sample objects in GameObject-GenerateObjectAnchorWipesBottle to test.When I build the app it just freezes after opening the camera.Any idea how Object tracking is done.I was testing using Unity 2018.1.1f1,Arkit2,Xcode 10_beta and testing device ipadpro 2017 model.I have set the deployment target to 12.0 in XCode.I dont know what I am doing wrong here

 

There is a bit of documentation in the https://bitbucket.org/Unity-Technol.../src/arkit2.0_beta/docs/WhatsNewInARKit2_0.md file.