Roblox WikiRoll for cards
Card rolling is the documented way to build your army. [1]
Fight with the army
The listing connects card collection to battles against enemies. [1]
Explore cooperative bosses
Boss battles with friends are an advertised activity. [1]
Reassign upgrade points
Use the Stat Reset system when the goal is to reclaim upgrade points for a different allocation. The developer describes point reassignment, not a full account reset. [2]
Collect expedition rewards
For Auto Expedition, the developer says the same team repeats completed expeditions and rewards wait in mail. Check mail for those rewards. [3]
This guide summarizes the linked sources; it has not been tested in-game.