Disk-imager usage explained

Created VM and connected SD card to it and run the script.
=> [FAILED] You must export or pass G_GITOWNER and G_GITBRANCH to the script

Could you explain steps little bit more detailed

NAME LABEL SIZE RO TYPE MOUNTPOINT
sdb 28,9G 0 disk
├─sdb1 128M 0 part /media/parallels/75DE-42E3
└─sdb2 28,8G 0 part /media/parallels/dbc7e15d-65fb-4aa3-a603-96fe97e3a6bd

Filesystem Size Used Avail Use% Mounted on
/dev/sdb1 127M 55M 73M 43% /media/parallels/75DE-42E3
/dev/sdb2 29G 2,6G 25G 10% /media/parallels/dbc7e15d-65fb-4aa3-a603-96fe97e3a6bd