Receive Notifications from Google Sheets When Checkbox is Checked

[TIMAI2]

I have the spreadsheet side of things working, just need to setup the app side.

Google Apps Script Function:

function buildMessage() {
  var ss = SpreadsheetApp.getActive();
  var sh = ss.getSheetByName('TaskList');
  var shi = ss.getSheetByName('toItoo');
  var rg = sh.getDataRange();
  var vals = rg.getValues();

console.log(vals);

  var msgs = [];
  for (var i=0;i<vals.length;i++) {
    if (vals[i][3] == true) {
      msgs.push(vals[i]);
    }
 }

 if (msgs.length > 0) {
console.log(msgs);

shi.getRange("A1").setValue(JSON.stringify(msgs));

  var alert = "";
  for (var i=0;i<vals.length;i++) {
    if (vals[i][3] == true) {
      sh.getRange("D" + (i+1)).setValue(false);
      alert += vals[i][1] + ", ";
    }
 }

showAlert (alert + " will receive messages");
 }

}

function showAlert(msg) {
  SpreadsheetApp.getUi().alert(msg);
}