Dishwashers do a pre-wash to get most of the big stuff off, then a main wash to finish up. If you use the capsule-things, there’s only soap for the main wash.
If your dishwasher has two compartments, then put detergent in both as one is for the pre-wash and one for the main wash.
If it doesn’t have two compartments, then just put some detergent loose with the dishes for the pre-wash.