where i can find work-will sample code or tutorial for beginner?

I am start from this page:
Getting Started with Vuforia in Unity 2017.2:
https://library.vuforia.com/articles/Training/getting-started-with-vuforia-in-unity-2017-2-beta.html

but when i get this step: Adding digital assets
i can not understand this line :
You’re now ready to add digital content to augment your target. You can do this by simply adding your assets as children of the target in the scene hierarchy.
i can not find astronaut mode stand on image target just like tutorial , then i import an assets from unity store ,but i can not adding my assets as children when i drag to the image targets , how can i do this step?(I can add a cube as children,but i can not do things like tutorial say......

at last , i import Vuforia Core Samples as a new project ,but it does not work ,no AR camera ,no image target , no astronaut stand on the image......

so,where is sample code or tutorial for beginner?

 

When you import the Core Samples into your project, there is a directory created within your project structure called "scenes" which contains various Unity scenes that demonstrate the features of Vuforia. Have you opened these and experimented with the objects present within them?

Thanks!

 

I can verify that after downloading the samples for AR VR they really do not work. Is there something that we must do as an extra to make it work?

 

Can you provide more information on what you mean by "do not work?" What Unity and Vuforia are you using?