check the manual
and there's a very good video that comes with that part of the academy.
There are some alternatives for parts of the game's manual targeting. I personally use the 3'15 trick to measure speed:
Use the notebook to get distance and AOB, and to get speed, measure the distance that your target travels in 3 minutes and 15 seconds. You can time it with your chronometer and use the map to measure the distance.
Speed= 10 x distance (in knots)
example= 0,7 kilometers becomes 7 knots