function addLinksFromSheet() {
  var sheet = SpreadsheetApp.openById("YOUR_SPREADSHEET_ID").getSheetByName("Sheet1");
  var data = sheet.getDataRange().getValues();

  var document = DocumentApp.getActiveDocument();
  var body = document.getBody();

  for (var i = 0; i < data.length; i++) {
    var searchPhrase = data[i][0];
    var hyperlink = data[i][1];

    var search = null;
    var count = 0;
    while (count < 1 && (search = body.findText(searchPhrase, search))) {
      var searchElement = search.getElement();
      var startIndex = search.getStartOffset();
      var endIndex = search.getEndOffsetInclusive();
      searchElement.asText().setLinkUrl(startIndex, endIndex, hyperlink);
      count++;
    }
  }

  document.saveAndClose();
}