Create S-Drive File Objects
Every object you want to use S-Drive with must have an associated S-Drive File object with either a master-detail relationship or lookup relationship where the file object is the child. You can create your file object using a spreadsheet and following these instructions.
Once your file object has been created, see Configuring Custom S-Drive file object on Lightning Page or Classic Override Page for S-Drive.
If you want to create a trigger to prevent a record from being deleted if there are files attached to it, see (Optional) Create a Before Delete Trigger for Custom Object