Absolutely No Training Necessary! Insert optional Clevercat jumbo liner if desired. Add 2″ to 4″ cat litter. For initial use, add a small amount of your cat’s feces/urine. Use without the lid on the first day and begin to use a lid on the second day. Most Importantly: Cats are intelligent and curious by nature and will instinctively understand how to use Clevercat. NEVER disturb your cat during its litterbox use!.