Toilet training your cat, using Citikitty. Citikitty is a 6 ring potty training system This videos shows Ziggy going from ring 0 to Ring 2 and what he does wrong and how he corrects himself. I also highly recommend using sewer safe litter. (unless you have really good pipes!)
Training a cat to go on the toilet is hard work. It took almost 3 months to get to ring 2. Be prepared to clean your bathroom everyday, my experience is that it will become a litter bomb. Litter was literally everywhere.I live in a one bedroom apartments and only have one toilet.
You must be patient and use positive reinforcement. Zelda his sister is not as far as him, but I'm hoping she will catch up.
Citikitty on Amazon : https://amzn.to/2SLG7Cj
Here are all my Instagram pages:   / ziggyandzeldacat_  
Ziggy's back up page :   / black_cat_ziggy  
Zelda's back up page :   / tabby_cat_zelda  
Music by https://www.bensound.com