Just some starting ideas on what you can do with the robot.
Drive a Pattern with Your Robot
Uncomment the drivePattern() function call in the loop, as show below. Remember, // identifies comments that are not run by the program. So when we remove the // that line will now run. Upload the edited program to see what happens after you flip the toggle switch on the robot.
Use the Ultrasonic Sensor to Drive Up to a Wall and Stop
Uncomment the driveUpToWall() function call in the loop, as show below. Comment out the drivePattern() function like //drivePattern(); Since we don't want to run both functions. Upload the edited program to see what happens after you flip the toggle switch on the robot.
Try to Follow a Line with the Robot
This one requires a line on the floor to follow and may take some adjustments to the function to get it working based on the lighting and brightness of the floor and line.
Use the Phone App Input to Trigger Events on the Robot