Dishwasher. my dishwasher lately has not been cleaning well-the soap dispenser opens, but at the

Question

my dishwasher lately has not been cleaning well-the soap dispenser opens, but at the end of the cycle, most of the soap is all clumped in the dispenser, and there are food particles and film all over the dishes. Please advise what i could do to troubleshoot, as i do not want to call in a repairman at this point-Thanks!