What your manual says is common to most dishwashers.

You can tell if your dishwasher has a pre-wash cycle if it does a short run, then you hear it draining, and then it does a longer full run. I expect it probably does.

Also, you can always add a bit of detergent to the main compartment of the dishwasher for prewash. The normal detergent compartment has a lid so the the detergent stays dry until the main wash cycle, and most prewash compartments are just an open tray.

Come to think of it, if there is a latching door on the detergent tray, your dishwasher definitely has a prewash cycle, or else they’d skip the door entirely