Luddite requires basic assistance

I understand the premise of Autopsy, I am having two issues I cannot resolve myself after 5(!) weeks:

  1. I am unable to create a image of a xiaomi phone, in order to use Autopsy.

  2. Autopsy itself does not detect any (!) drives on my pc. I see threads regarding this and am reading all of them but cannot answer my own question.

In conclusion, how does one create an acceptable image (including cache on phone) for autopsy to work on? Any tutorial that doesn’t involve Rick Roll is apprecaited.