[ubuntu] New disk unallocated space

I am relatively new to Ubuntu and PC building in general.

I just a built a Desktop PC and installed Ubuntu. Its been up and ruing fine so far. But I just realized that one of my internal disk drives is not being utilized.

I have one 250gb ssd drive, the OS is currently installed here
and a 2tb SATA internal harddrive, this drive is currently not being recognized (screenshots from gparted is attached)

Please advise on how to add the second harddrive
How to plan space allocation (i.e. what files/folders should reside on SSD versus internal harddrive)
I intend to install windows eventually on this PC too (maybe as dual boot or on VM)

Please advise

Thanks

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