The fundamentals of aircraft navigation rely on a map that corresponds with what you are seeing on the ground, and the measurements of time, speed and heading.
If we know exactly where we are at any previous given point in time, we know which direction we flew, at what speed and for how long (time), then we can never be lost.
We use speed and time to work out distance flown, then if we know the direction, we simply measure the distance in the correct direction and our location is known.
CASA requires all pilots to keep accurate records of planned flights. Once in flight the pilot must also keep an updated version of the flight details with a mandatory position pinpoint or fix at least every 30 minutes.
When planning legs or waypoints along the way, it will reduce your workload if easily recognisable features are used at least every 30 minutes. The best features are either as you pass abeam or cross a town, cross road, railways, or rivers. Certain shapes in rivers or roads are also easy to identify.
It is also good practice to put small pencil markers along each leg indicating either 10 nm, 6 minute or 10 minute intervals. These become extremely useful when trying to calculate elapsed or planned time intervals.
Most of this will become much clearer in the next lesson where you will see an actual planning sheet.