I don't know about this particular data structure but I know that all CGAL geometric structures implement iterators for faces, vertices, edges, etc. so that's how you would access them. You probably won't have control over the traversal order or random access though...

You should definitely have a look at CGAL documentation and examples, they are very well made:

https://doc.cgal.org/latest/Triangulation_3/index.html

You should also ask their support for more precise question with code snapshot:

https://www.cgal.org/mailing_list.html

Good luck,

Bruno