How do I transfer some iMovies to a new mac?

My ProBook is 10 years old. I bought a new iMac. After doing a complete transfer of the old Mac to the new Mac, I see that the iMovies did not transfer. There are empty slots for them with the names of the files in the new Mac iMovie, but clicking on them, it says the file does not exist. I don't need to transfer all of them, just one or two here and there.