I put 4 bricks on the backdoor step so my cats were level with the flap. I then sat outside on a garden chair (cats were inside) and waited and waited, tempting them with goodies.......eventually they both pushed their way out ! I repeated this a few times on both sides of the door - much to the amusement of my neighbours !! Mine were 12 month old rescue cats too, It didn't take that long for them to get the hang of the flap. The female was first out, clever girl, the boy is a bit dumb but followed her lead. Good luck!