Dishwasher is draing slowely how do I fix

Dishwashers don't just drain. The water is pumped out. Slow draining means pump is defective or there is a restriction or crimp in the drain hose.

Inspect hose in sink cabinet. Disconnect hose from air gap or drain, point into bucket and run thru drain cycle.

If you find nothing, remove dishwasher and inspect hose. Remove hose from pump, inspect pump discharge port for obstruction.

Restriction could be food particles in pump sump. If pump sump has a removable cover, remove and inspect.

The same pump that pumps the water out, pumps the water around during wash and rinse cycles. If dishwasher pumps water around during wash and rinse as it should, obstruction is not likely to be in the pump.