You need to place them in the folder or folder they were originally in when they were imported into LR. Once that is done and you restore the LR catalog they should all show up.
If you can't place them back into there original folders then you will need to Re-Import them.
Carbonite should give you the option to restore the photos to the exact same directory that they were in previously. Then open the backup of the catalog file, and all will be well.
If you can't place them back into there original folders then do NOT re-import. Re-importing is a huge mistake. Put them somewhere else in the same folder structure/hierarchy, and follow these instructions: Adobe Lightroom - Find moved or missing files and folders