Insert data into multiple table in entity framework

I have 2 tables like below. am using DB first approch

public class Team
{
    public long Id { get; set; }
    public string Name { get; set; }
    public string Description { get; set; }
}

public class Employee
{
    public long Id { get; set; }
    public long TeamId { get; set; } // foreign key reference fom Team table
    public string Name { get; set; }
    public long ReferedBy { get; set; } // foreign key reference fom employee table
}

now i have to insert data to both table once. for example i need to insert data like below.

before introducing Referred By column i was using below code to insert.

        Team team = new Team();
        team.Name = "Team1";
        team.Description = "Some Description";

        Employee E1 = new Employee();
        E1.Name = "Jon";
        Employee E2 = new Employee();
        E2.Name = "Harish";

        team.Employee.Add(E1);
        team.Employee.Add(E2);

        DBEntity db = new DBEntity();
        db.Set<Team>().add(team);
        db.saveChanges();

after introducing Referred By Column how i can insert these reference to database.