Test mission

Testing with inbuilt simulator

There is a button for testing a flight mission using the built-in simulator in the bottom right corner of the terrain map:
Clicking on it launches a virtual version of the UAV along a given route. The virtual UAV has characteristic differences:
Testing on a 3D map:

Testing with SITL

If you are a professional and are well versed in the intricacies of Ardupilot technology, you can further test the task by loading it into the SITL (Software in the loop) program.
To do this, launch SITL console and connect to it from GCS in one of the following ways:

Without MavProxy: choose TCP connection
With MavProxy: choose UDP connection

After this, proceed exactly as if you were connected to a real UAV:

Save flight mission on UAV
Click on 'Start engine' button
Click on 'Take-off' button
Click on 'Autopilot' button

Testing on a 3D map:

Reminder

If you have forgotten the meaning of a button, simply hover your mouse over it and wait until a tooltip appears.