There's no set way that you have to do it. That's where a lot of confusion comes in with planting. You can get good results using several different approaches to planting. Generally speaking you want to cultipack small seeds(clover) and use a disk with no cultipacker to cover large seeds(corn). However as Spoon said, if your dirt is really worked up fine and real soft, a cultipacker will press large seeds deep enough that you don't need anything other than the cultipacker to cover the seeds. If you were going to plant clover on this same soft dirt, you'd definitely want to run a cultipacker over it before broadcasting the seeds so that when you cultipack the 2nd time, you don't bury the tiny seeds too deep.
Most of the time I don't even use my cultipacker when planting corn, beans, peas, etc. I just broadcast then run the disk over the field with little to no angle set and a piece of railroad rail dragging behind.
