Next and Prev actions are available when you connect a button to a Dataset. They allow to browse between the items of this dataset for display on the same page.
However (and here is where it starts to be confusing), they do not allow browsing between item pages.
Dynamic Pages create the relation url → filter → dataset . So a dynamic page with url
/{year}/{event}
is translated into a query
wixData.query('collection')
.eq('year', 'year value')
.eq('event', 'event value')
.find()
This query may return one or more elements - those are the elements of the dynamic dataset.
The next and prev operations (both APIs or the Dataset and the Button actions) are moving the dataset across those results of the query - if there is only one result, they will not have any effect.
So for each page - like /2017/ambassadors-summit, for instance, we have a single page, for which we find all the items in the collection with year 2017 and event ambassadors-summit. The dataset can show all those items on the page - like in a gallery.
The challenge with Dynamic Pages is that the definition, the url /{year}/{event} does not imply what is the ordering between the pages - what is the next page after /2017/ambassadors-summit? How do we expect to define this ordering? We are still thinking what is the best approach here.