I have Asus N552VW with the firmwarre mode set to Legacy and the following disks: * 128GB SSD: my windows 10 is installed on it * 2 TB HDD partitioned exactly into two partitions
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
X can be
s depending on their controller and
Y is a sequential number or letter respectively.
In your particular case
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.