Painting a car is pretty hard man. You need to sand it down at least to the bare paint. Slap bondo on the dents then when you think the car is good to paint you need to prime it up and look for anything you messed up on. And you will mess up! Then you need to repair the repaired parts then prime again look to see if you messed up so on aand so forth. Once the car is good then you need to prime then wet sand it down. Prime a bit more then wet sand again. prime a few more times. Then wet sand once more then paint. Once painted sand down AGAIN! Then respray Once the car is good to go. You clear coat it then wet sand again. Then clear cost once more then wet sand again then the car can be polished up! Goodluck.