Yes, concentrate on the failure to crank condition FIRST.
Jump start try from a different vehicle is also a good idea, assuming all electrical connections are good and clean.
Since the lights dim when you try to start, shows that the electrical part of the ignition switch is working.
I'd put in neutral, and momentarily jump from the large positive terminal on the starter solenoid to the smaller terminal on the starter solenoid. If that doesn't spin the engine, tap on the starter a couple of times with a hammer and try again.
Jump start try from a different vehicle is also a good idea, assuming all electrical connections are good and clean.
Since the lights dim when you try to start, shows that the electrical part of the ignition switch is working.