Hello
I’m sorry to hear about your cat.
I think that you need to find a veterinarian or a veterinary technician who can show you how to do this. I would also recommend you start gentle physical therapy and feed canned food to keep the feces soft and able to pass more easily.
Hello.
If you follow my blog at kmdvm.blogspot.com I have a few articles on this. I would use a soft splint and rest. These kittens grow and the legs strengthen and they can have normal lives. If you are anywhere near me in northern Maryland I will help.