You may refer with this sample code snippet on how to use Google Apps Script for querying Google trends. For example, this function read input from the spreadsheet and sanitize it, then call up queryGoogleTrends to perform actual query and finally display the actual result:
function startQuery() {
sheet = SpreadsheetApp.getActiveSpreadsheet();
// start the query
var result = buildQueryString(sheet.getRangeByName("q").getValue(),
sheet.getRangeByName("cat").getValue(),
sheet.getRangeByName("geo").getValue(),
sheet.getRangeByName("gprop").getValue(),
sheet.getRangeByName("cmpt").getValue(),
sheet.getRangeByName("date").getValue()
);
// display the resulting link in a cell
sheet.getRangeByName("Query_Result").setValue(result).setBackground("yellow");
var csv_result = generateCsvDownload(sheet.getRangeByName("q").getValue(),
sheet.getRangeByName("cat").getValue(),
sheet.getRangeByName("geo").getValue(),
sheet.getRangeByName("gprop").getValue(),
sheet.getRangeByName("cmpt").getValue(),
sheet.getRangeByName("date").getValue()
);
sheet.getRangeByName("CSV_Download_Link").setValue(csv_result).setBackground("yellow");
}