Hi, i would like to help you.
I am a forensic expert and what you are doing i simply my daily work.
I am dutch don't know if the NL in your name reffers to the netherlands

however as in the thread is said you first need to make a backup/image.
I personally would not recommand you DD cause if you do not exactly know what you are doing you could overwrite your disk(with the btc on it)
I would advise you to use FTK imager and make an .E01 backup
https://accessdata.com/product-download/ftk-imager-version-4.2.0it's a simple visual program. If you did this and you want my help please DM me. Next step is autopsy

good luck for now