Titling - here you can define what label is used for the links on the page, you can have a generic next and previous labels or you can tell the system to use page titles instead.

Labels - allows you to customise your general labels for next and previous, what even you define in these text boxes is used when you choose Next & Previous Labels in the prvious Titling section.

Navigation - arrows allows you to add arrows to the next and Previous labels

Loop -,this would mean the menu works in a continuous loop, so when you get to the last page and click next it would return to page one.

System Pages - means you allow CMS admin pages to be part of the loop sequence, you may not have this option is your access doesn't allow, but it should never be enabled.

Ordering - This allows you to define what order the pages should be in for the next and previous, the most logical order would be the Sitemap order but you can choose another route depending on your needs.