Help with the ending

One of the things I have learned about aging is not to fight your limitations-just learn to work with them and your golden years will be much more enjoyable-and less stressful.. This is a good example of that thinking. I recently watched this film for the first time to aid a fellow researcher in authenticating some of the era farm equipment used in the sets. For instance, the hoop rake, seen in the film, a classic Cyrus McCormick contraption, is improperly fitted for a mule team and was a later tractor drawn model(I have one of both)that was homed handed to look like a much earlier model.
So be it.
Now to the film-I have problems understanding the dialogue(whispers) between the twins through the movie. Regardless of how closely I listen, I can't understand the final scenes that tell the story. I will not watch it again or read the novel because that is just not in my list of needful things(only persons over 60 will understand that). A script might help but would not reveal the director's intent.
Perhaps, someone could explain it-the final cellar scene until the final apparition in the window some weeks after the tragedy and the bit about the cut lock. English is my third language and that also is a problem.

Also, I found a note written in longhand on the plain DVD folder that says " stills available for pullblade"
"Pullblade" was the slang name given for the tracblade seen at the end of the film because they caused the operator to 'pull' more debris into a pile himself that the blade would ever push-obviously it is not a era piece. The trac is a early military design, which of course, would be impossible if the era is the late 30's because it could only been functional if restored from parts made in the Ukraine during WWI. A Russian authenticator has already said it is, or was, put together just for the film's sets.
I would love to see those stills if anyone has them.

Pa