An SACD ISO should import just like any other audio format. For help on Importing,
see the wiki.
Once imported, you should see the tracks in MC, depending on the ISO, it can list the artist, album and track info, but I've also seen ISO's that import without showing any tags (artist and album info empty).
Albums with empty tags are either all the way at the end, or at top. The new ISO should also be under playlists recently imported.
When you find it, you can doubleclick a track to play it.
If you still fail to get it to import or play, please give mode details about the steps you're going through. Screenshots of error messages or popups also help.