In Data Backup, Recovery, and Archiving > Restoring your databases > Before you restore, replace the sixth bullet item with this text:
For a full restore, the store files (by default, the .iq files), the catalog store (by default, the .db file), and the transaction log (by default, the .log file) must not exist in the location to which you are restoring. If any of these files exist, delete them or move them to a different directory before doing the full restore.
A full restore destroys all old database files and re-creates them. Manually deleting the store, catalog store, and transaction log files protects you from inadvertently performing a full restore.