How did I replace all footage from one imovie project with another

Question

I have three projects in my project library A, B and C. While editing B I somehow accidentally copied all my clips from project B into project A, erased all project A footage while the title remained the same. I want my project A footage back and can't find it. Time machine wasn't set up at the time (I thought it was automatically already going from the day I purchased it). Undo functions only go back once. Three people at Apple have no answer, saying that you can't transfer contents from one project library piece to another while still in the project library part of the screen. I'm sick if it's lost because it took forever to edit, but I want to figure out what I did so I don't accidentally do it again. If I didn't transfer from project to project, how did a copy of B get into my A file and erase its contents?
Project A seems gone, as the orange lines in the event library clips indicating which parts have been used are also gone.

Answer 1

Choose Go to Folder from the Finder's Go menu, provide /Users/ as the path, drag one account's home folder to the other's desktop, and move the items inside it to the desired locations.
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