I want to play different landing animations based on falling time
falling speed might be better to base your calculation on, rather than falling time, because total falling time could cause weird results, if the character was launched from the ground onto the top of a tall building, with the peak of their jump near the roof. they would just start to fall slowly, but they have been in the air for a while, so they would play an animation which is probably more aggressive than it should be.
as for knowing how long something has happend, in general, you can use GetGameTimeInSeconds, store it in a variable, then later, you can GetGameTimeInSeconds, and subtract that variable, to know elapsed time.
Thank you so much .