Save checkbox value when I create a new asp.net identity user?

I want the user to be able to choose among some check boxes when I create a new asp.net identity users and save the result. I also want to get the value for each checkbox for each user. Each checkbox is an area (e.g London).

I have a table Area

ID | Name

Together with the applicationUser I guess I need a third table with many to many

Area.cs

public class Area
{
    [Key]
    public int ID  { get; set; }
    public string Area { get; set; } 

    public virtual ICollection<ApplicationUser> Users { get; set; }
}

IdentityModels.cs

public class ApplicationUser : IdentityUser
    {
        public virtual ICollection<Area> Areas { get; set; }
}

This gives me a third table ApplicationUsersAreas

I have added this to the view Account/Register.cshtml

<input type="checkbox" name="myarea" value="1" />
<input type="checkbox" name="myarea" value="2" />
<input type="checkbox" name="myarea" value="3" />
<input type="checkbox" name="myarea" value="4" />

How do I save the checkbox result for the user and how do I get the result for the user? E.g I want to save that the user checked the checkbox London and Denmark.