function onFormSubmit(e) {
const folderId = "1y40PNXYXSm7Ue_b6nbVnauz7dzKiKj4u"; // Please set top folder ID of the destination folders.
const form = FormApp.getActiveForm();
const formResponses = form.getResponses();
const itemResponses = formResponses[formResponses.length-1].getItemResponses();
Utilities.sleep(3000); // This line might not be required.
// Prepare the folder.
const destFolder = DriveApp.getFolderById(folderId);
const folderName = itemResponses[0].getResponse();
const subFolder = destFolder.getFoldersByName(folderName);
const folder = subFolder.hasNext() ? subFolder : destFolder.createFolder(folderName);
// Move files to the folder.
itemResponses[2].getResponse().forEach(id => DriveApp.getFileById(id).moveTo(folder));
}