I have created a webform with Google Apps Script that links to the Google sheet at backend, based on https://www.bpwebs.com/create-web-forms-to-get-data-from-google-sheets/
I have created a check-in system, that requires users to enter their ID and the search will return their information stored in Google Sheet. Now I want to add a button for the visitor to click, so that their check-in timestamp (the time which they search for their ID on the webform) can be added to the Google sheet. Multiple check-ins with different timestamps for a single person may happen too.