@CharlieMedina, the 256GB SSD should be your boot drive.

Depends in your configuration. I think R8 has an ssd in which the OS (Windows ) is loaded, and you have another drive, typically a sata for storing stuff, data, etc.

Honesty this is all just jiberish to me so I don’t really know what that means.

I'll try a direct answer to your question:

Is windows 10 automatically downloaded to the ssd or the hard drive if I get the 256 ssd with the 2tb hdd?

Windows 10 automatically downloaded to the ssd.

Is it not possible to ask dell or the seller

There was a related post on here where the poster was asking why the OS was not installed on the ssd hence it may be the other way round.  Reason for it being that way was ssd have shorter life span compared to traditional magnetic drives. 

According to the Dell Service Manual, if your R8 shipped with an M2 "• with an M.2 drive, the M.2 drive is the primary drive."   Service Manual   So in theory it should be plug and play with windows installed on the M2 SSD. 

But I recall the post that you're talking about, and I suppose Dell must make mistakes here because my computer which I bought directly from Dell shipped with a 32GB Optane drive set as a storage drive, and the Optane accelerator turned off.  Now, this made my job of junking the Optane drive easier so I didn't complain, but imagine if someone who knows nothing about computers bought a system like this, and went about using it without knowing they paid for components that aren't even being used properly.