If you are wondering how Xenoblade Chronicles 3's Flame Clock mechanic works, it's simple. In short, the Flame Clock serves as a stat-increase mechanic early on during Chapter 1. During Chapter 1, you can fill the Flame Clock to earn stat increases. As the Flame Clock's gauge increases, character stats for your party will increase. However, the stat boost gained from the Flame Clock early on in the game will not last. As time goes on, the Flame Clock will slowly decrease, so you will need to keep the Flame Clock full to maintain any stat increases gained.
How to increase the Flame Clock in Xenoblade Chronicles 3
To increase the Flame Clock in Xenoblade Chronicles 3, you must slay enemies. Slaying enemies generates a small amount of life force to fill the Flame Clock. Because of this, we don't recommend worrying about filling the Flame Clock too much, as simply playing the game and slaying monsters as you find them earns you enough to keep the Flame Clock filled.
Does the Flame Clock matter later on in Xenoblade Chronicles 3?
Yes, it does. In short, players won't need to worry about filling the Flame Clock anymore for story reasons, and the Flame Clock will instead serve a role in the story involving various colonies after Chapter 1.