I just set up Touch ID on my new Mac Mini M2 w/ Ventura. Ventura shows you a picture of your Mac Mini power button and says to quick press it twice. I tried lots of different quick press spacings - the one that finally worked was a very quick, incredibly quick, double press. They have to be full presses that would turn off your Mac Mini if you held them for more than an instant. Light taps, like on a trackpad, will not work. When it works you get a box asking you to confirm your password. Then you can proceed to enter your finger print.