function getOrders(){
  var ss=SpreadsheetApp.getActive();
  var sh=ss.getSheetByName('Orders');
  var rg=sh.getDataRange();
  var vA=rg.getValues();
  for(var i=3;i<vA.length;i++){
    var column1Value=vA[i][0];
    var column2Value=vA[i][1];
    //You can loop through all of the orders data this way and copy the data that you want from each column to the appropriate place on overview