This app is a demonstration intended to showcase the camouflaging interaction discussed in the CHI 2017 paper "Chameleon Devices: Investigating More Secure and Discreet Mobile Interactions via Active Camouflaging".
First, take a photo, then place your phone on the surface, adjusting the image to help it blend in. Then, select the colours you'd like to use for the three notification types (or let the app do this for you). Finally, wait for notifications to appear, and watch your phone subtly alert you. To replay a notification, either touch the screen, or wave your hand over your phone.
Recent Android system changes have removed the Chameleon app's ability to show subtle updates without also displaying system notifications. In order to experience the original notification interaction, please first disable notification "peeking" for the three third party apps for which notifications are displayed (Facebook, WhatsApp, SMS).
For more information about the research and overall project, please see: http://cs.swan.ac.uk/~cssimonr/#Chameleon
It looks like you tried out Chameleon during the prerelease phase before we added usage instructions. Please note that this app is meant to be a demonstration of subtle notifications, rather than a replacement for all types of alerts. Hopefully you can give it another try to see how the app is meant to work.