2 yr old won’t stay seated to use the potty

FTM to a little girl. She tells me when she pees or poops and has started asking to have her diaper changed. To me, this says she’s ready for potty training but I have no idea what I’m doing. There is soooo much information out there and my head is spinning, I don’t know where to start.

She won’t actually sit on the potty. Seriously. She will lower her butt on it and within milliseconds, she’s up and gone. Poop, pee, it doesn’t matter. I‘ve tried going on the actual toilet when I’m trying to show her how to sit on the potty, but that’s an unfortunate disaster that results in a bare ass toddler running through the house while I’m trapped mid stream on the toilet… and an accident on the floor.

Just wondering if anyone else’s kiddo had the same issue and what you did to get them to stay seated for the performance?