Replacing a draft of a project from a word file

I have a 15k word story that I’ve sent out to someone else to edit. I exported the story as a word file so the editor could read it and make comments with track changes and so forth. I received the word file back.

I’d like to make the revisions in the word file then import it back into Scrivener. The problem is that in Scrivener, I’ve separated the story into multiple scrivenings and I’m not sure how to get the story back in the proper structure.

Does that make sense? How should I do this?