I think the display is self explanatory, but just in case, here's a brief description.
The number in the center is the distance reported by the sensor nearest an obstruction, this can be in cm or inches.
The bar graphs on the left are for the front sensors, the graph on the right is for the rear.
Each bar graph has 4 columns, one for each sensor, left to right.
Each pixel height on the bar represents 10cm, a full bar meaning that distance is less than 10 cm, a single line bar being greater than 61cm and a small dash indicating no reading.
The arrows indicate which sensor is reporting the nearest obstruction. The middle arrow indicates front or rear, one arrow to either side indicates the side of the inside sensor, a double arrow the side of the outside sensor.