Okay, take a hose and fill it manually with the timer set on wash, and see if the machine starts to agitate. (If it does not you can drain it by moving the timer to spin.)
If it runs try replacing the water level switch. If not, the timer is suspect.
You may want to replace both, and then if it works replace the old parts and see which one is defective, send the one you don't need back. If you buy parts from this site and they do not fix things you can return them.