Recently I attempted to install Kali on an external hard drive, since my internal drive was pretty much full. I managed to get through the installation after a few problems that were eventually solved. However, now I can not find the external drive in BIOS, and as such, can't boot from it. I am, however, able to view the drive in Windows' Disk Management. I noticed none of the partitions have drive letters. I'm still fairly new to Kali, so I don't know if that is a problem.
Here's a screenshot of the external drive partitions:


Here's a screenshot of the partitions on a Kali virtual machine that works (albeit with much smaller partitions):


One difference I noticed is that in the external drive, all partitions have "100% free", and the File System field is blank. In the end, my question is what can I do to get this working? Any help is appreciated.