Requirement: The file you want to share must be in a format that is compatible with the "collaborative work" feature. You must also be an admin of the group in which the file was uploaded.

If you want to share a file in the Sdui cloud for editing, first go to the cloud folder where the file was uploaded.
Now click on the three dots to the right of the file name and then on "make public":

The lock icon to the right of the file name opens as soon as a file has been released for editing.

To specify that the file should no longer be editable by all members of the group, repeat the process described above and now click on "Make private".