The Boot Loader goes onto your boot device and as the boot device is your first drive: /dev/sda) that is where the Linux Boot Loader¹ should go.
In your particular firmware, disks are labelled my their disk brand names and as a Liteon is an SSD, that's where the existing OS gets booted from.
In Linux, disks are named /dev/XdY where X can be h or s depending on their controller and Y is a sequential number or letter respectively.
In your particular case /dev/sda and dev/sbd are your disks and dev/sda1 is the first partition on the first disk, /dev/sda2 the second partition on your first disk, /dev/sdb1 the first partition on your second disk, etc...
Note¹: It's called GRUB2 of GRUB for Grand Unified Bootloader.