This is counterintuitive, because on a standard Mac keyboard, the command key is placed right next to the space bar… where the Alt key will be on a Windows keyboard.
The problem with using a Windows oriented keyboard with a Mac, is not that the functions are different, it’s the layout that causes issues. For example, if you connect a Windows keyboard to a Mac, the Windows key will work as the “command” key, and the “Alt” key will work as the “option” key.