How do CT and the Action Timeline work?

CT (Charge Time) must be filled to a certain point before a unit is granted a turn.
CT is consumed when the unit takes action, after which they must wait for their CT to accumulate again before their next turn. CT fills quickly for units with high AGI.
CT consumption increases in the following order.

1. Waiting without taking action.
2. Moving or taking action.
3. Moving and taking action together.

You can swipe through the Action Timeline displayed on the left side of the battle screen to help keep the flow of battle in mind. You can also tap the Action Timeline button at any time when you are attacking or using abilities to check the best timing to cast abilities or when a unit's next turn will be.
Tap the different icons to see which unit they relate to, and use this information to help win battles more efficiently.