Play games
Choose the game that interests you and play itfor free.
Complete the quests
Every game has some quests for which you will receive Soul Gems.
Receive rewards
You can exchange your Soul Gems for Steam Wallet top-ups, game keys, CS:GO Skins and other rewards.
Who wouldn't want to celebrate Christmas on early November?
https://fate-go.us/news/?category=NEWS&article=%2Fiframe%2F2020%2F1112_re_underworld%2F
Different from other seasonal events, this one actually is pretty important to the story (of Ereshkigal in particular). So don't skip it. Santa Altera is a good support with NP charge, so get her at all cost. But don't burn your apples early on, because right after this event should be the annual unlimited lotto season, and you'd want to spend apples on that instead.