Uploading to Reference Artifacts

I’ve been trying external reference artifacts for the first time, and am I right in thinking WandB will not handle uploading files to external stores? So I can use reference artifacts to link to pre-existing files/folders on S3/GCS/Azure blob, and I can then use WandB to download those files from the external stores once they’ve been linked to a reference artifact, but I can’t create/upload them with WandB to begin with - they must already exist on S3/GCS/Azure blob?

Or if it is meant to be possible to do the upload with WandB I’m struggling to get it to work with an Azure Blob - it looks for pre-existing files, doesn’t find any, and adds no references to the artifact.