Does the information on the **Riding Mode Usage** screen relate to the time I have been riding or the distance covered?

The distance covered in active riding mode is counted, regardless of whether or not you receive support from the drive unit. (For example, if you stop pedaling, let your eBike freewheel, or ride faster than 20 mph, you will not receive any support from the drive unit.)

You can find out how much effort you expended and how much the drive unit contributed using the Power Share tile.