This project is to automate the attendance data processing for CTA affilated schools. Follwing youtube video can help you to get the credential to read the google sheet (Sample[https://github.com/mvkrish/attendanceautomation/blob/master/CTA%20Tamil%20School%20-Attendance-Sample.xlsx] is added here in the repo).
https://www.youtube.com/watch?v=vISRn5qFrkM
After that keep the client_secret.json and chromedriver.exe or executable in path and run the python file. if you use jypyter you can run the python file in parts to get to know the code.
Hope this helps, if you have questions send to me at @krishbal in twitter