Install Zorin on 2nd physical HD

I have a desktop computer with two physical hard drives. I have Debian installed on the first and I would like to install Zorin on the second. The 2nd HD is already formatted with two primary partitions: one to receive Zorin and the other (much smaller) to be shared by the two systems for data exchange.

I booted Zorin from a USB thumb drive and started the install process. I chose “something else” for the installation setup. The installer presented me with two windows: one listing ALL hard drives and ALL partitions; the other as the destination for the boot loader. No where did it offer me a choice for “install destination.”

My question: How do I install Zorin as the 2nd OS - on a physically separate disk - on a machine that already has a Linux OS? What kind of nightmare can I expect with GRUB2?

From what I recall, there is a dropdown menu in the lower part of the screen once you select “Something Else” - this dropdown menu is for drive selection. The upper part presents all partitions.

Thanks. I’ll give it a second go and be sure to capture screenshots if things still look funky.