I am completely new to AR. I created 3 markers using vuforia and unity and each display a 3d model. So far when I show a marker to my webcam it displayes the 3d object. Now I have been trying to create on touchscreen function. I want that when the user seeing my 3d models, when he touches them a message pops up. I have tried out different code from different forums but none worked. Could you please help giving me a detailed description of what i need to do?