Ruehan's Analysis of Guard Division 3 Documents

Ridena is not actively engaged in the war(s) until very late, so the goals of the Guard battalions based on it are more of a back support thing.

Basically:

until 2439, not up to much.
2439, support begins for a faraway campaign. This ramps up, as more support is needed. Units are trained here, sent elsewhere.
2439-2448, this ramps steadily upwards. The strategy changes from "a quick campaign" to "a long and painful campaign".
2448, there's an additional campaign that Ridena is training/supplying for, that of a rebellion more nearby. This ramps up as the previous set of goals ramp down.
2450, the overall strategy changes hands; in addition to supporting different places, the orders-from-high seem to be less precise, less carefully tactical.
2453, there's actual fighting on and near Ridena, and increased coordination with the Legions, less so with Skyguard.
As of 2453.155, there are no more entries.