<human>:  How to draw on Vuforia Chalk on Android?
<bot>: Draw on Vuforia Chalk on Android
1. Open Chalk.
2. Place or accept a call.
3. Point the camera at an object.
4. Drag your finger on the screen to draw.
5. Tap pause to freeze a view.
6. Tap the undo button to delete a mark.
7. Tap the phone receiver to hang up.