What are these parts & how do I test them?

It does not turn over? Your first photo is the STARTER RELAY. NOTICE the "push on wires." The YELLOW wire gets "start" voltage when the key is twisted to "start."

The remaining wire goes to your CLUTCH SAFETY SWITCH so the clutch must be in when cranking. Remove that wire and hook a jumper from that relay terminal to ground. See if the engine now cranks with the key

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The BOTTOM photo is the coil ballast resistor. It is either good or bad, as a rule. WHEN STARTING by using the KEY, the ignition switch supplies power directly to the coil through the BROWN wire on the right hand side in the photo. This goes directly to the coil + terminal

So if the ballast is bad, usually, the engine will "fire" when cranked, but die when the key is released to "run."

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The MIDDLE photo is the voltage regulator. Not important to get the car running. You could unplug it, or not, does not matter to fire and run the engine.

Do yourself a huge free favor. Visit these two links and download yourself a FREE shop manual for your car. At the MyMopar site, there is also more / other info posted

http://www.forabodiesonly.com/mopar/showthread.php?p=1970088617

http://www.mymopar.com/index.php?pid=31

THANK you for posting pertinent information about what you are working on. Many, here, lately, do not