Bodywork Questions, also dumb mistakes

What about the fender on the car points to lots of bondo? Just trying to get a better eye for this kinda stuff. Also, if the fender off the car is in better shape, would it be beneficial to fix it before bolting it on, or bolt it on and then continue on to bodywork?
Lots of cracks in the damaged area. Also look like a chunk of bondo came out when it was hit. You can strip the fender on the car, and see how bad it is. Only you can decide whether to repair the fender on, or off the car. Just depends on if it's easier to work on bolted to the car.