Hello Joel,
When I start download_debian, nothing happens. Is anyone else experiencing this?
Please make sure that you use the current version, i.e. 19.03-p3. That being said, sometimes fetchurl gets stuck (total and now stay at '0.0'). It may help to start the 'download_debian' subsystem multiple times or to wait long enough (it might take a few minutes for the retry timeout to trigger). This is a regression within the current CE release and we will address the issue soon.
How can I manually use my own .iso?
One way would be to put the .iso on another Ext2 or FAT32 formatted USB stick and to use 'Inspect' in the leitzentrale to copy the file over.
Regards Josef