function sendEmail() {

  var sheet = SpreadsheetApp.getActiveSheet();

  var startRow = 2;  // First row of data to process

  var numRows = 2;   // Number of rows to process

  var dataRange = sheet.getRange(startRow, 1, numRows, 3) // Fetch the data

  var data = dataRange.getValues();

​

  for (var i = 0; i < data.length; ++i) {

    var row = data[i];

    var emailAddress = row[0];  // First column

    var message = row[1];       // Second column

    var subject = row[2];       // Third column

​

    MailApp.sendEmail(emailAddress, subject, message);

  }

}