No need to make duplicate threads. Please remove the other one or ask a moderator to do it. It causes more confusion if replied to in multiple places.
I don’t know how many (m)Gs a stomp is. The sensor itself should not break until around 5000G. I’m pretty confident that your whole setup wil fail before that. Certainly your foot. At worst your stomp G-spike will be out of the measurement range and clipped to the maximum reading. But measuring the actual peak does not seem to be important for you. Just registering the bump in the noise of walking/brushing against something is what you want. I don’t know how to quantify that. I’d say experiment.
The WakeOnShake board is powered through the same power inputs/JST connector. Which takes at most 5.5 volt. Which would light up white leds when arranged in parallel. But not a bunch of leds arranged in series for 12 volt. Applying 12 volts to the power inputs would damage it.
Where did you read that? Product decription and Hookup guide only mentions up to 5 volt or so. More damages it.
Demo code is an arduino sketch (for on the attached Arduino). Read through the Hookup guide for an example how to use it. Sending commands to the WakeOnShake can be done with the Arduino Serial monitor or programs like Putty or Terminal or whatever.