Push nut broke upon installation
I guess the trick is to gently tap the push washer on to the assembly or is there another way to install that push nut??
Thanks for contacting us. I'm afraid we don't sell the push nut by itself. I'm not sure who would, to be honest. We are only able to provide this as a kit.
I'm not sure what video you watched, but I don't think any kind of hammer is necessary. The manufacturer suggests pushing it around the lever stem with a flat blade screw driver. Just make sure to take your time and push it a little at each side, going around it in a circle.
I've also known some professionals set the lever on a block of wood and place a small socket from a socket wrench set over the shaft to tap the push nut on.
It can be a little tricky to install, though it is definitely possible to do it yourself. If you're having trouble, though, you may want the help of a locksmith.