Normally, I wouldn't start with a champion, but this one is an exception, it's absolutely central to how the faction works.
Knight of Seasons isn't optional; it’s your biggest weapon. Its cost to stats ratio, once boosted, is unmatched. Gaining the necessary magic is relatively easy, as you can discard events and immediately retrieve them.
This unit is another reason to consider a front gate: it allows Knight of Seasons to pressure the opponent right away. But you need to ensure that it enters play with at least 3 boosts, which is harder if Eldiri isn't nearby to provide the first one. Also, ensure you have the right events in your discard to retrieve. You'll use those same events to protect it, healing it and repositioning it after an attack.