@ac60eec8 It takes time. Especially if they don't have a trained cat they can learn from. You can put "Cat Attract" in there. Maybe try a different type of litter if they don't seem to like it. But really, just keep putting them in there when you think they need to go. Eventually they will figure it out. 

 @7725718e Their mother can teach them. Perhaps she’s being overwhelmed by also feeding them though, so she hasn’t yet. What is Cat Attract? I want to see if we have them here. 

 @ac60eec8 Ahh, I didn't realize that mom is around. Ya, they will learn from her. Cat Attract is basically a cat nip powder you can sprinkle on the litter. They also sell litter with it included.