The section File System Management belongs to Linux Fundamentals module.
Download the VPN file from HTB Academy and run the following command in the same directory:
sudo openvpn academy-regular.ovpn # Make sure you have openvpn installed.
Use the lsblk command:
lsblk
For this specific task, you have to spawn an actual Pwnbox in the browser. You will see partitions listed under vda.