Runs but no water

My dishwaher runs, but no water comes out. I removed the catch thing at the bottom and there is dirty water in the tub underneath - I do not know if these two things are related. I need help! I did attempt to read through the manual that is posted here but I am pretty ignorant when it comes to these types of things. I could really use some suggestions before I break down an call a repair man. Thank you so much!

you may have a water valve problem in dishwasher . but first shut off power to d/w at breaker. remove bottom cover, you might need torque screwdriver to remove screws. then put your hand inside of base of d/w +feel around for water. if you feel water there is probably a leak. i use a shop vac to remove water. once water is removed . the d/w should star to fill wih water. i usually remove outer door + metal cover behind door attached to base, gives me alot more room to look around ,use atrouble lamp to see better turn d/w on +observe where water comes out ,maybe leaking water valve on left or front sump hose .see what you see+we will take it from there