Open a page in new tab

function openPPCDashboard() {
  var js = " \
    <script> \
    window.open('PASTE_DOC_URL_HERE', '_blank'); \
    google.script.host.close(); \
    </script> \
  ";
  var html = HtmlService.createHtmlOutput(js)
    .setHeight(10)
    .setWidth(100);
  SpreadsheetApp.getUi().showModalDialog(html, 'Now loading.'); // If you use this on Spreadsheet
  //  DocumentApp.getUi().showModalDialog(html, 'Now loading.'); //  If you use this on Document
  //  SlidesApp.getUi().showModalDialog(html, 'Now loading.'); //  If you use this on Slides
}