Load data to datagridview C#

Hello,

First of all you want to load data from database to any one datatabel or dataset then using the looping statements using to load a data like Datagridview1 , 
I think you already have a structure of Datagridview1 column header and row headers.

Am using datatable for example,

private void selectAreaColor()
{
    SqlConnection con = new SqlConnection("Connection String");
    SqlCommand cmd = new SqlCommand("Your Select Statement", con);
    SqlDataAdapter da = new SqlDataAdapter();
    DataTable dt = new DataTable();
    da.Fill(dt);
    if (dt.Rows.Count > 0)
    {
        for (int y = 0; y < dt.Rows.Count; y++)
        {
            string starttime1 = dt.Rows[y]["start"].ToString();//I don't know how to declare it to get it from the database
            string stoptime1 = dt.Rows[y]["stop"].ToString();//I don't know how to declare it to get it from the database
                                                             // Get the start time and end time inputs and the selected meeting room
            DateTime startTime = DateTime.ParseExact(starttime1, "HH:mm", null);
            DateTime endTime = DateTime.ParseExact(stoptime1, "HH:mm", null);
            string selectedRoom = dt.Rows[y]["RoomNo"].ToString();//I don't know how to declare it to get it from the database

            // Loop through the rows in the DataGridView and find the matching row

            foreach (DataGridViewRow row in grdMeeting.Rows)
            {
                if (row.Cells[0].Value.ToString() == selectedRoom)
                {
                    int rowIndex = row.Index;
                    // Loop through the columns and compare the start and end times with the time slots
                    for (int i = 1; i < grdMeeting.Columns.Count; i++)
                    {
                        DateTime columnTime = DateTime.ParseExact(grdMeeting.Columns[i].HeaderText, "HH:mm", null);
                        string _HeaderText = grdMeeting.Columns[i].Name.ToString();
                        if (startTime == columnTime)//|| endTime == columnTime
                        {

                            grdMeeting.Rows[rowIndex].Cells[_HeaderText].Style.BackColor = Color.Blue;

                            if (startTime == endTime)
                                return;
                            else
                                startTime = startTime.AddMinutes(30);
                        }
                    }
                }
            }
        }
    }
}