OK. The ignition solenoid clicks. That shows there's power available and the switch is working.
Either the power isn't reacing the starter or its jammed.
Is the starter jammed? Can you turn the engine over by hand?
The solenoid is like a heavy duty relay that switches the high current supply to the starter.
We know the solenoid is clicking so, is there power actually getting to the heavy duty contacts to be switched?
Check the heavy screw connections on top of the solenoid (http://i.ebayimg.com/00/s/NDY3WDUwMA==/z/TtkAAOSwJb9WqWyo/$_1.JPG)
You should see 12V on one and 12V on both when you try to start.
Then see if there's 12V appearing at the starter motor when you try to start?
You may have a bad starter, bad solenoid or simply a loose connection.
XXX, April 2016