The tachymetre is pretty easy, but the rest I have no idea about.
To use the tachymetre, measure how long it takes you to do something. Where the second hand stops, that's how many you can do in one hour. It doesn't work if it takes you more than 1 minute to do something.
For example, if it takes you 30 seconds to drive 1 mile, you can see that the second hand points to 120. That means you can drive 120 miles in 1 hour.