I'm glad you're enjoying the game!
I understand the wording may be confusing, but I didn't find a better way to describe it. Basically, this is what it means:
- Players start the game with three intervention tokens.
- These tokens may be spent on a game, all three of them.
- These tokens may be spent on a single turn, all three of them (e.g. you may force the opponent to reroll three times in a row).
- After the game finishes, players start a new game with three tokens, regardless if they spent them.
Remember that Krig: Intervention matches are played in a best-of-three format (you must win two games to secure victory).
Let me know if it's still unclear, and I'll gladly try to help.