The main condition: the air temperature should not be higher than -40 degrees. The colder the better.
Needed: mug, hot water. It will be good if the saluting person is at some height.
As noted, the photographs were taken against the sun. They turn out better if there are no clouds in the sky, because the salute pairs giving the salute an additional effect merge. Best time for photographing: sunrise and sunset.
It is necessary to prepare and set up the camera in advance: set it to high-speed multi-frame shooting: shutter speed 1/800 and higher. Since you are taking photos against the sun to protect the camera’s matrix, it is recommended to use polarizing and ultraviolet filters.