a little help with bit torrent (im a newbie)

That depends on which bittorrent client you are using. If you are using the old bittorent client that used to be included in Riadiator, then I've got no idea how to go to it directly. (I know you can, I just haven't used it for a very long time)

If you are using Transmission, you can access it by going to
http://IP.of.nas:8181/Transmission
where 8181 is the rpc-port set in Transmission (i think it's the default port, but I might have changed it for myself).
You can also use a program like Transmission Remote dotnet or Transmission Remote GUI to manage your downloads. These are programs you have to install on your computer and can be used to connect to Transmission on your NAS.

im using bittorrent and have a shortcot of the adress at a lnk in my browser

Obviously this is a very late response, but I thought in case others have this same question, I would answer the following-
I'm not sure what your exact setup is and whether that would make a difference, but on my older Duo, which came with Bittorrent as a standard add-on service, the port to listen on is 8080.