Create a checkbox in a cell when a other cell contains a date

I'm a noob to scripting and i have a spreadsheet that contains dates in some cells in row 0. Now i like te automatically create a checkbox in row 5 if row 0 contains a date. I use the checkbox to create or delete a event in the spreadsheet to a calendar. Now a need to put the check boxes in manually when i put in a new date.The script i'm using you can see down here.

spreadsheet i'm using

//**
// * Adds a custom menu to the active spreadsheet, containing a single menu item
// * for invoking the exportEvents() function.
// * The onOpen() function, when defined, is automatically invoked whenever the
// * spreadsheet is opened.
// * For more information on using the Spreadsheet API, see
// * https://developers.google.com/apps-script/service_spreadsheet
//*/
function onOpen() {
  var sheet = SpreadsheetApp.getActiveSpreadsheet();
  var entries = [{
    name : "Export Events",
    functionName : "exportEvents"
  }];
  sheet.addMenu("Calendar Actions", entries);
  
  var sheet = SpreadsheetApp.getActiveSpreadsheet();
  var entries = [{
    name : "Delete Events",
    functionName : "deleteAllDayEvents"
  }];
  sheet.addMenu("Delete events", entries);


};

/**
 * Export events from spreadsheet to calendar
 */
function exportEvents() {
  var space = " - "
  var sheet = SpreadsheetApp.getActiveSheet();
        //var sheetName = sheet.getName() als je een tweede sheet gebruikt
        //if(sheetName != "Events"){
           //return
        
  var headerRows = 1;  // Number of rows of header info (to skip)
  var range = sheet.getDataRange();
  var data = range.getValues();
  var calId = "stichtingmotardstein@gmail.com";
  var cal = CalendarApp.getCalendarById(calId);
  for (i=0; i<data.length; i++) {
    if (i < headerRows) continue; // Skip header row(s)
    var row = data[i];
    var date = new Date(row[0]);  // First column
    if(isNaN(date.valueOf()))
      continue;                // skip row, go to the next row 
    var numb = row[3];
    var title = numb.substring(11,6) +space+ row[2];
    var loc = row[1];
    var id = row[4];              // Sixth column == eventId
    // Check if event already exists, update it if it does
    try {
      var event = cal.getEventSeriesById(id);
    }
    catch (e) {
      // do nothing - we just want to avoid the exception when event doesn't exist
    }
    if (!event) {
      //cal.createEvent(title, new Date("March 3, 2010 08:00:00"), new Date("March 3, 2010 09:00:00"), {description:desc,location:loc});
      var newEvent = cal.createAllDayEvent(title, date, {location:loc}).getId();
      row[4] = newEvent;  // Update the data array with event ID 4
    }
    else {
      event.setTitle(title);
      event.setLocation(loc);
      // event.setTime(tstart, tstop); // cannot setTime on eventSeries.
      // ... but we CAN set recurrence!
      var recurrence = CalendarApp.newRecurrence().addDailyRule().times(1);
      event.setRecurrence(recurrence, date);
    }
    debugger;
  }
  // Record all event IDs to spreadsheet
  range.setValues(data);
}

function deleteAllDayEvents() {
  var ss=SpreadsheetApp.getActive();
  var sh=ss.getActiveSheet();
  var rg=sh.getRange(2,1,sh.getLastRow()-1,sh.getLastColumn());
  var vA=rg.getValues();
  var cal=CalendarApp.getCalendarById("stichtingmotardstein@gmail.com");
  vA.forEach(function(r,i){
    var id=r[4];
    if(id && r[5]) {
      cal.getEventById(id).deleteEvent();
      sh.getRange(i+2,5).setValue("");
      sh.getRange(i+2,6).setValue("TRUE");//just to reset the checkbox
    }
  })  
}