Devo 7, 7e - Realflight Sim , how to

I just bought Realflight 7 with Elite remote, and want to use either my Devo 7 or 7e with it. The version I bought does not come with an interface cable and I don't see it available for sale as a stand alone item. What do I need to do to get either of these remotes to sync with it. This will be my first time using a sim, so I will probably need very good instructions on syncing these remotes.