SO I am an old man and not sure what the root folder is, can you tell me where to place the dll file I downloaded?

dll file goes in your rocksmith folder

so where you installed rocksmith on your computer is the root folder

SO I am an old man and not sure what the root folder is, can you tell me where to place the dll file I downloaded?

root folder is usually where rocksmith.exe is, like in your steam library, exact default path would be like "C:\Program Files (x86)\Steam\steamapps\common\Rocksmith2014"

 

gl hf