Subwoofer help

hello all, I’m a new to me 2016 Prius 3 owner,I would like to install a subwoofer and was wondering if anyone had a step by step procedure to do so. I want an under the seat self amplified unit and already have the sub. I have installed 3 of these units over the years so I have an idea, my problem is where to get power from, the audio source and how to rout it to the sub. I’m have no knowledge on how to remove panels on this car and it is in great shape and do not wish to trash it. If you have pics of your install that would be awesome as well. Thanks....dusty

 

Thanks, but this looks way beyond my technical skills, all I want to is add an under the seat sub. I was wondering where to come through the fire wall for power and the best way to pickup the audio signal. Also I’m not sure about removing panels, I would hate to break anything because even being used it is pristine