Position based

The Walk behavior’s Mode parameter when set to Position-based lets you control the puppet’s walking simply by modifying the Position parameter (2nd parameter below the Mode parameter — not to be confused with the Transform behavior’s parameter of the same name). Usually you add keyframes to that Position parameter. When the character is moving, their legs will animate, and when they are not moving, they’ll stop. Compared to animating using the arrow keys (with Mode = Left & Right Arrow keys), you have much more control, though the arrow keys are useful for live interactive animations.

For more on the Walk behavior, see https://helpx.adobe.com/adobe-character-animator/using/behaviors/body-directly-controlled.html#walk