jamesmalexander
All users each have their own storage, which gets mounted as /sdcard when that user is active. Skybox sees those files under the Local Files option. Populating that storage is somewhat difficult though, because, as Lucy mentioned, USB MTP access is not offered to the secondary user in the headset. (It was, for a time, but isn't anymore.) Also, each user only has access to their own files, so copying between users is complicated.
If you want to be able to populate the secondary user's files, you'll need to become familiar with "sideloading" (running Android apps that aren't on the Quest store.) A very helpful app would be CX File Explorer, since it can pull files from a PC over SMB, accept incoming files from a PC over HTTP, copy from FAT32 USB drives, and move files between a user's folders on the headset.
It would also be great if Skybox offered a copy file option for SMB, WebDAV, and USB sources. That would let the user copy the movie to their own storage from a PC or NAS device from within Skybox.