Okay, one (1) click means the starter relay (actually a small solenoid) is picking, but probably has bad internal contacts, and is not passing voltage on down to the starter solenoid. Two clicks and/or dimming of the lights would mean the problem is closer down toward the starter.
The solenoid you are looking for is located inside the dog house cover. Remove the cover and look on the dog house inner wall just forward of where your right foot would be if you were sitting with your foot on the accelerator. It can be a buggar to reach painlessly, but it's there.
You will know it when you see it, cause it looks just like any old start relay you've seen on Ford fender wells for years.
It may work if you give it a good wrap with a mallet, or you may have to replace or repair it.
Here is a simple diagram of the Ford start circuits. The relay that we are discussing is the small one on the right side of the page.
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Unless this relay picks (and closes the contacts) the solenoid down on the starter will not be activated.