Auto body repair & detailing: small ding on cab roof, touch up paint, sand paper

Question
It's a small ding from a rock that landed on it during a storm. I will try the bonding as you suggested. Then i guess a little touch up paint will finish it. My question to you is how do i apply the bonding correctly and also the touch up paint? I'm trading in the car for a new vehicle and don't want to get screwed by the dealer on my trade in value.
thanks.

Answer
Sand area with 80 or 180 grit sand paper to roughen up the spot. then mix bondo and spread with a bondo spreader to fill dent let dry. Then sand spot with 180 grit sand paper to make smooth. then touch up with primer and paint.
                Thank you for the question!
                Ken