** My dishwasher won't drain .Don't know how to fix it. Please hepl this single mom become a more handy mom. **
If it isn't just a plugged drain hose/pipe like John suggested you're going to have to provide more information about the dishwasher so we can find out what design it is (they're not all the same) and what specific components of it might cause such a problem.
The "model number" is the key reference to the appliance you have. If you post its brand name and model number we'll see if we can suggest anything else to check if the drain hose, etc. isn't the cause. You can find tips for locating the model and serial number tag on your appliances in the 'Repair Parts' section of my site linked below.