What are the review queues?
What is the newly added review section and how to use it properly?
The review section was already there but now there is a nice link to it (thanks to this feature request). It looks like its only shown if there are no suggested edits (suggested edits is part of the review section).
You can use it to review several posts:
You can use this tool to improve the overall quality of the site. By using the powers given to you by the community. For example,