Preloading will visit pages based on the settings and generate cache, just like any other visitor to the site.

How does it work?
Preloading works as the background process and it can be triggered on following events:
- Click “Preload Cache” item on the admin bar (Powered Cache -> Preload Cache)
- Purge page cache.
- When an expired page deleted. It will preload automatically.
Limitations:
- In order to get advantage of preloading, it only works when page cache has enabled.
- It works with public post types and public taxonomies.
- It preloads 1000 posts by default when activated for posts.
- It preloads 100 terms by default when activated for public taxonomies.
- Each preload requests wait for 5 seconds to not overload the server. This value can be changed with powered_cache_preload_request_interval filter.