587 Doesn't work well

I bought a Kenmore 487 last week. I ran it once with liquid / gel soap, which left big clumps all over the dishes and nothing was clean. I had to re-wash everything by hand. I decided to try some new soap - dry - and it worked better, but it didn't come out of the dispenser completely and most of the soap was sitting on the bottom of the dishwasher when it was done. I just started another wash without adding any soap, and it seemed to work better. I realize it's not a top of the line model, but I've only run the dishwasher three times since I bought it, and my dishes have gotten clean once - and then not completely. Am I using too much soap or does it need to just run a couple of times before it works? Any other suggestions to try before I get totally frustrated?