Connection to sql-server databases

I have used SQL management studio to create a database. Which connection string should I use now. Also the database does not appear in the Server object explorer why? I have worked in past on Dot Net this but I had never handled the database creation part myself. Please help. Thanks

My own attempt was:

 private void Form1_Load(object sender, EventArgs e)
        {    string constr = @"Data Source = Diabete; Initial Catalog = Cibi; Integrated Security = TRUE;";

            using (SqlConnection con = new SqlConnection(constr)){
                con.Open(); //here get error (cannot find server or database)
                using (SqlCommand cmd = new SqlCommand()) {
                    cmd.CommandText = "";
                    using (SqlDataAdapter da = new SqlDataAdapter(cmd))
                    { }
                }
            }
        }