asp.net Login Session

I'm new in asp.net webform. I am trying to create a Login Session. I have my Login.aspx with a button. In the action of this button I execute the login:

if(username.Text == "" || password.Text == "")
    {
        ScriptManager.RegisterStartupScript(this, this.GetType(), "Pop", "$(function() { requiredLoginFields(); });", true);
    }
    else
    {
        var query = from u in db.Users
                    where u.Username == username.Text &&
                          u.Password == password.Text
                    select u;
        if(query.Count() > 0){
            Session["Logged"]="Yes";
            Session["User"]=username.Text;
            Server.Transfer("Home.aspx", true);
        }

        else
            // Working on it
    }

On every other page I verify the session in the Page_Load:

protected void Page_Load(object sender, EventArgs e)
{
    if(Session == null)
    {
        Response.Redirect("Login.aspx";)
    }
}

My questions. Is it the correct way to implement a login session? Do I need to check the session in every Page_Load of all my webforms?

Is there a way to load automatically my Home.aspx? I mean when I run the project I would like to open http://localhost:64716/ and it load my Home.aspx.

Thank you