connection with 3 tables in Entity

Question

Hello,

I have 3 tables in SQL dataBase: Movies, Viewer and Movies_Viewer (= that shows which viewer saw which movie).

the client will insert Viewer name and Movie name and with the Entity I want to insert it to the 3 tables I have (with linq for example), but how should I know what ID gets the movie and the viewer to insert it in the third table?

should I insert to the 2 tables and then call another function that insert the ID's to the third? how do I have all the data?

please halp me!

this is my code:

Is it wrong to do like this?

[WebMethod]
        public void InsertToDB(string viewerName, string movieName)
        {
            InsertToViewerTbl(viewerName);
            InsertToMoviesTbl(movieName);
        }

        private void InsertToMoviesTbl(string movieName)
        {
            var db = new MoviesEntities1();

            var movieNameTbl = new MovieNameTbl();
            movieNameTbl.MovieName = movieName;

            db.AddToMovieNameTbls(movieNameTbl);
            db.SaveChanges();
        }

        private void InsertToViewerTbl(string viewerName)
        {
            var db = new MoviesEntities1();

            var viewerNameTbl = new ViewerNamesTbl();
            viewerNameTbl.ViewerName = viewerName;

            db.AddToViewerNamesTbls(viewerNameTbl);
            db.SaveChanges();
        }
    }