Real time co-edition is not available on Elium, two users cannot edit story at the same time.
However, you can manage co-creation using the "Drafts". When saving a story as a draft, you can invite other users to contribute, add information or either verify the content.
It's important that you save the story in a space in order to create a collaborative draft. If you save the draft in your personal content, it would be considered as a personal draft and you will not be able to invite other contributors. On the left of the platform's landing page, you will find a tab to access your draft list.
Elium has a function for version management to update files, while preserving the history of the versions.