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();

Answer 1

I suggest that you do the tutorial.
http://www.codeproject.com/Articles/539816/Relationships-Using-Entity-Framework