2. Slider plugins or bundled with themes typically require you to manually build a slider by choosing images from the media library to include in the slider, and are not normally suitable for generating sliders that automatically retrieve the required data
3. What I suspect you want. You have a custom post type where the posts have several images attached as a repeating custom image field, and when you display the post you want to display those images in a slider.
This is a common enough subject, but requires some effort from your part to get it working.
It basically involves ensuring that the slider assets (CSS and JS) are enqueued on the page, that the format of the markup output matches what is required by the slider, and instantiating the slider (if it doesn't happen automatically).
The principles are the same for whichever slider library you use.
I have provided instructions for the flexslider library before, where you can specify options to, for example, including thumbnail navigation on the bottom: hidden link
We have a pending update to our documentation about this, and details of what's involved are described here: hidden link
