Enabling paging on an actionbar means that the bar will switch to another set of actions when either using shift + number or shift + mousewheel.

Under the default settings, shift + 2 would switch the actions shown on ActionBar 1 to that of ActionBar 2, shift + 3 would switch to ActionBar 3, etc. The functionality is similar to that of how the Blizzard main actionbar works.

Page skip sets how many pages to skip when paging a bar. If page skip is set to zero, then you will cycle through all bars when paging. If its set to 1, then you'll cycle through every other bar (shift + 1 on the main actionbar would go to bar 3, for example).