Issue parallelising loop in R

Question

I have a function which loops through a table containing Url to data for downloading, and names that will be given to the downloaded file.
I am trying to get the following code to work in parallel - so that files are downloaded in parallel rather than sequentially- however, when the code is run it seems to do the latter. I would really appreciate any help identifying what the issue is!

 library(foreach)
 library(doParallel)
    
### Setup parallel backend to use many processors ###
   cores=detectCores()
   cl <- makeCluster(cores[1]-1) #not to overload your computer
   registerDoParallel(cl) 
    
### The Loop ###
  foreach(i = 3:200, (nrow(Df))) %dopar% {
        URL<- print(Df$Url[i]) 
        FN<- print(Df$FileNames[i])
        LOCAL<-file.path("Users/anon/desktop/books", paste(FN,  ".mp4", sep=""))
        download.file(URL, LOCAL, mode="wb")
        }