This is where it gets fun. To restate what a crank/no start is, it's when you turn the key and you can hear the engine moving but it's just not catching and running. You can first eliminate all the above causes in this article because you have confirmed that your starter, cables, and battery connections are likely good. If they weren't, you wouldn't hear the engine turning over when you turn the key.
There are several causes of this type of no-start, but I'll cover the basics here. An engine needs three things to run:
- A fuel supply; without fuel, the engine won't run.
- A spark (for gasoline-powered engines). The spark is delivered to the combustion chamber via the ignition system. If you have a fault here, the engine won't start.
- Mechanical integrity.
There are actually quite a few mechanical issues that can cause a no-start condition with an engine. This video covers the basics of dealing with a crank/no start condition to get you started.