Tactics Cards unlock on Day 2 of the season proper - a collectible system split into Core Cards (kept permanently at season end) and regular cards (which convert to Profession EXP when the season closes). Build your loadout intentionally rather than equipping whatever drops first; a deliberate set meaningfully outperforms a random one even at the same card rarity.
Around Week 5, every warzone splits into one of two factions - Kage no Sato or Koubutai. From Week 6 through Week 7, the Copper Wars are fought Wednesday and Saturday over each faction's Alliance Centers, and Copper rank directly sets your season reward tier, so treat these war days as the season's main event, not a side activity.
Progress this season also feeds the Armament Institute's path toward T11 troops, which unlock in the following off-season - worth starting early even if the payoff comes later.