I have two form's Search Codes for these Search Codes i want to add try catch exception

I have two form's Search codes i need to add try catch exception for them.

first form is including Tank Details there i select data by tank no, date, start time, end time and time duration. for this i want add if tank no and and time duration is selected only it should allow for Search option if not it should show error message.

Second form is including Alarm Details there i select alarm type, date, start time and end time. for this i want add if alarm type is selected only it should allow for Search option if not it should show error message.

Sorry, I don't know how to try, Please help me.

Alarm Details Search part
private void BtnSearch_Click_1(object sender, EventArgs e)
        {
            linkLabel1.Enabled = false;
            Search.Enabled = false;
            btnSearch.Enabled = false;
            btnPrint.Enabled = false;
            Cursor.Current = Cursors.WaitCursor;
            var startDate = dateTimePicker1.Value.Date.Add(new TimeSpan(dateTimePicker2.Value.Hour, dateTimePicker2.Value.Minute, dateTimePicker2.Value.Second));
            var endDate = dateTimePicker1.Value.Date.Add(new TimeSpan(dateTimePicker3.Value.Hour, dateTimePicker3.Value.Minute, dateTimePicker3.Value.Second));
            DateTime dct;
            DataTable tab = new DataTable();
            tab.Columns.Add(new DataColumn("Active Time"));
            tab.Columns.Add(new DataColumn("Type"));
            if (comboBox1.SelectedIndex == -1)
            {
                tab.Columns.Add(new DataColumn("Name "/* + (comboBox1.SelectedIndex + 1)*/));
            }
            else
            {
                tab.Columns.Add(new DataColumn("Name " /*+ (comboBox1.SelectedIndex)*/));
            }
           
            tab.Columns.Add(new DataColumn("Value/Contents"));
            foreach (DataRow dtr in dt.Rows)
            {
                if (!DateTime.TryParse(dtr.ItemArray[0] as string, out dct))
                    continue;
                DateTime tim;
                DateTime.TryParse(dtr.ItemArray[1] as string, out tim);
                dct = dct.Add(new TimeSpan(tim.Hour, tim.Minute, tim.Second));
                if ((dct >= startDate && dct <= endDate) && (comboBox1.SelectedIndex > -1))
                {
                    if(comboBox1.Text == dtr.ItemArray[1].ToString())
                    {
                        tab.Rows.Add(dtr.ItemArray[0], dtr.ItemArray[1], dtr.ItemArray[2], dtr.ItemArray[3]);
                    }
                 
                }
            }

            dt = tab;
            dataGridView1.DataSource = tab;
            linkLabel1.Enabled = true;
            Search.Enabled = true;
            btnSearch.Enabled = true;
            btnPrint.Enabled = true;
            Cursor.Current = Cursors.Default;
        }

Tank Details Search part
       private async void BtnSearch_Click(object sender, EventArgs e)
        {             
            linkLabel1.Enabled = false;
            Search.Enabled = false;
            btnSearch.Enabled = false;
            btnPrint.Enabled = false;
            Cursor.Current = Cursors.WaitCursor;
            var tgs=await SearchCSV();
            foreach(var gts in tgs)
            bs.Add(gts);
               
            linkLabel1.Enabled = true;`enter code here`
            Search.Enabled = true;
            btnSearch.Enabled = true;
            btnPrint.Enabled = true;
            Cursor.Current = Cursors.Default;         
        }