Tempo is the order of Actions in both Combat and Out.
In general out of Combat, Tempo is only used as a tie breaker for when multiple actions are happening simultaneously.
In combat, each round takes 10 seconds, and the Tempo of an action determines how much time it takes to complete that action.
Timescale
Timescale represents the duration of each round and turn when considering Tempo.
By default, combat lasts about 1 minute with each round being 10 seconds.
When talking to an individual, this may last 10 minutes to an hour, with each round being 1 minute or 10 respectively.
When at a large event, this may last the whole day, with each round being 1 hour long.
Timescale should be apparent when a Scene starts, and controls how long Conditions last.