To generate a preview embed link for a file, the file must be uploaded to
Box. For most file types, conversion is triggered automatically upon upload.
However, for video and 3D files, it is triggered upon first preview. No explicit
action is required by the user to begin conversion. In either case, conversion
is triggered only once per file, and the generated assets are available for as
long as the original file is stored in Box.
To upload a file using the Box SDKs or directly with
the APIs, you need to use the client ID and App Token that are generated
during application setup to authenticate your
application.