/wp-content/plugins/preload-fullpage-cache directory, or install the plugin through the WordPress plugins screen directly.This plugin doesn't come with any settings screen on purpose. Settings screen may be included in the future, depending on the feedback from the users.
Usually, you can check if a post is served from the cache or not by looking at the headers info. So, create a new blog post or update an existing post and look for its headers info. For example, if your site is behind Varnish, you may see the 'Age' information that is greater than zero. Uncached posts (for example, a search query such as example.com/s=test) will have 'Age' as zero.
Unfortunately, no. But, there is a workaround that requires some coding skills (such as how to extend a plugin). Please see this support thread for an explanation... https://wordpress.org/support/topic/custom-post-types-313/ . Thanks.
This plugin needs to fetch the new / updated post thrice in real time over the internet, just after publishing or updating. This is expected to slow down the whole process!