There is no legitimate, safe external web link to download individual Creation Club files like ccbgssse025advdsgsesm.esm or its corresponding .bsa archive. Downloading these files from third-party file-sharing sites exposes your computer to malware and can cause game instabilities.
This alphanumeric string is the internal filename for a module. CC : Creation Club BGS : Bethesda Game Studios SSE : Skyrim Special Edition 025 : The specific project ID advdsgsesm : The compressed master file format (.esm) ccbgssse025advdsgsesm download link
Most modern mods, especially the Unofficial Skyrim Special Edition Patch (USSEP) , now require this file as a "master". Without it, your game will likely crash on startup. There is no legitimate, safe external web link