I will say with my four of watching them from kitten to full grown is they learn on their own of their abilities & or not.. They learn how to handle climbing & potting in the litter box & just getting around in general.. Now I know with my Taccoa & Zolene their litter box has taller sides than the others.. Due to both babies use the sides to lean on for support..
I use those storage containers for Amy's litter box and half of the time she will walk into the box completely(facing the back), and let 'er fly and there are times she completely misses the box. That's why I use those disposabel pads outside all the boxes. (If she trys to squat, she falls so she does everything standing.)