Oh sorry for that!
You have to descend / ascend until you get to the retrival part.
Then you have to look at the radar and look for the blue circle (package).
Use controllpanel (Angle / Distance and Button) to launch a drone towards the package, where angle is 0-360 degrees and distance is 0-100 meters.
You can see your launched drone on the sonar as a pink ping, once you have launched it.
Thanks for playing, sorry for the lack of instructions :D