http://www.google.com Search for script examples and tutorials so that you can learn.
https://www.tutorialspoint.com/powershell/powershell_files_copy_files.htm
https://www.enjoysharepoint.com/working-with-file-modification-time-and-date-using-powershell/
https://stackoverflow.com/questions/36963250/schedule-powershell-script-to-run-every-hour