Car will not start, brand new battery, starter and alternator ok

Hello, I'm reading about what happens when you shut the vehicle off, and I'm reading also that you can't start it. I'm unclear as to what the concerns actually are. Either way, a no start concern - is this a situation where the engine cranks over but will not start? Or there is a click and no cranking? Or there is no click and no cranking? Share more information please.