Not sure if this helps or not as I'm a novelist rather than a screenwriter, but I tend to look at them in the opposite way (partly because I write in four acts):
The signposts are the acts for me. When we're dealing with the Situation throughline and we're in The Past, then it means the conflicts that are arising in that act and throughline are arising out of The Past. What Dramatica calls the Journey is, for me, the thing that transitions the story from one act to another (with respect to a particular throughline.) So for me, "The Past To How Things Are Changing" can be a scene or chapter or sequence where that big change takes place.
Not sure if I'm right on the theory side, so perhaps more experienced Dramatica people can clarify further.