Hi Rachel
I may be guessing wrongly at what you are trying to achieve but the basic difference between the Decision tree page and the connector pages is as follows:
The Decision tree page is meant for building a sequence of decisions and branching that is within that page itself not for linking to other Xerte pages. It also provides an overview of those choices at the end and the ability to view the other choices too. So its really a sequence of decisions and interactions within itself which also contains some additional functionality linked to those choices. Example via
xot.xerte.org.uk/play.php?template_id=116#resume=47
There is also a separate decision tree template for creating projects purely based around decision interactions e.g.
www.nottingham.ac.uk/toolkits/play_11196
The connector pages are meant for providing an interaction which, based on what the user does, connects to other pages or displays additional content. Example of each of the connector pages starting at
xot.xerte.org.uk/play.php?template_id=116#resume=35
These days you could also build the same kind of non-linear navigation by turning off the default navigation on any page and using xerte page links to link to different pages depending on what the user selects e.g. you could use a normal multiple-choice page with different page links in the correct and wrong feedback or use different xerte page links attached to text or images on a plain text page that then link to different pages in the resource. So you aren't limited to using the 3 different connector pages but obviously you can use those too.
HTH
Ron