To use Drive Badger, you need at least one USB drive:
Drive Badger supports 4 most popular drive encryption methods: Bitlocker and VeraCrypt (Windows), LUKS (Linux) and Apple FileVault (Mac OS). But it is your responsibility to obtain encryption keys and configure them on Drive Badger device(s) - without this, accessing encrypted drive won't be possible.
Here you can find the installation manual, divided between installing Kali Linux and Drive Badger itself. If you don't need to customize anything, here you can find the complete install script. This is the minimum.
Now, to really understand Drive Badger, you should also read about:
shutdown the operating system on target computer
connect the USB drive - preferably to USB 3.0 port
boot the computer from connected USB drive:
on the following screen, choose option Live USB Encrypted Persistence
after few seconds, you'll be asked for password - enter it
after a while, attack will start automatically in the background, while you will get the text console - you can use it as a disguise, or to show attack progress in the realtime
That's all. After approximately 2-3 minutes, your USB drive will contain a copy of all interesting data from that computer. You can then switch to another computer - and after finishing them all, analyze the collected data.