Whenever you create a KoreSound and you save it to your user sounds folder, the sounds is also written into the database and will be available via the Browser.
Note that KORE 2 does not scan the user sounds folder at start-up. In case you receive a KoreSound (.ksd) from another user or another computer and you place it into the user sound folder, it will not appear in the Browser automatically at next start. You need to do a scan of the user sounds. Go to KORE 2's Options menu, on the Database tab and trigger the Scan User Folders option.