Their natural curiosity will lead most cats to use the Litter-Garage with no prompting. You may find the following suggestions helpful to make the switch:
Prop open the cat flap for a few days.
Transfer some of your cat's existing litter to the new pan.
Place treats or catnip on the carpet pad in the chute, and gently encourage your cat to check it out.
Call to your cat from the window on the metal drawerbox and coax her to walk in.
Never force or push your cat through the cat flap.