Hi,
here is a starting point. move the character and it will kick the ball automatically.
few points to understand the system:
-- I added a capsule collider, because character controller is a special kind of physics object, so it's needed ( as far as I can tell)
-- the ball is checking for collision event, ONLY coming from the player ( I labelled the player with a "player" tag)
-- I get the velocity of the collision which give me the direction of the kick ( inverted ) so I multiply it with a negative factor to kick it away.
-- I also add an upward force to make the ball go in the air.
Have a go, if you have questions, don't hesitate.
bye,
Jean