I suspect you are using the trick I showed on Windows. That was specific to WSL 2 and won't work on OS X. Instead of finding that location, you will probably just have to mount a normal directory (any directory of your choosing using the dialogue). This is selected in the Volumes section under Host Path. The container path should stay the same as in the tutorial.
It may or may not take as long as I suggest in the video, since the filesystem operations work very differently between WSL 2 and OS X.