BMW E60 E61 5-series airbag passenger seat sensor mat replacement

Amateur guide on how to replace the sensor mat on a 2004 BMW E61 E60 5-series.
I didn't wanna just bypass the sensor with resistors and diodes. It didnt feel right to do that so I got the genuine spare part from BMW and replaced it.
This operation took me 3.5 h to complete whilst fiddeling around with the camera.