Hi.

Please look at the breakdown diagram Model GSD2220F00BB

Start with checking if the water shot off valve to the dishwasher is open! It should be under the sink.
Next, at the body parts diagram find the float and float switch in the left front corner. In case if the float will stock in an upper position or the switch lever is not pressed, water won't fill in.
Remove the kick panel and check the switch and float position. Also, check if the pump motor is making humming noise when the dishwasher is turned on. The motor could be jammed. If it is, unplug the dishwasher and manually turn the motor by its fan to release the shaft. You may succeed or may not, depends on how bad is the jam. The click you are hearing is most likely the drain solenoid activating.
If the float and float switch are both OK check the water inlet valve. If you have a multimeter and know how to use it, check if there is 120V AC going to the water valve solenoid terminals in the first two minutes of the wash cycle. If there is a proper voltage to the valve and water is not coming, replace the inlet valve.

Please keep us posted on the outcome.

Thank you.

Simon.