Replacing hard drive

I have a Dell OptiPlex GX280 that I want to replace the existing hard drive (original died). I would like to replace with two drives: SSD for startup and HHD for storage. Before someone tells me this is an older computer, I realize that but it has done everything I have wanted. I am not a gamer.

What can this computer handle? I have read that I can install 2TB. Is that the SSD and HDD combined or each?

Thank you