Question Is it possible to install Windows 10 on old Mac Pro with a new HDD ?

Thanks for your help, but i would like to install Windows on a new internal HDD without using Mac IOS at all, not running windows on a HDD where Mac IOS is already installed....Do you think it's possible ?
There is a section in the link about how to do just that. It is not a straight forward process like a typical PC.

Here is another similar link:

 
I dont see which section you are talking about :'(

Imagine my Mac Pro tower doesnt have any HDD, can a buy a new HDD and install windows on this mac hardware ?