How can i update more than 100 records in a report by a schedule?

How can i update more than 100 records in a report by a schedule?

I have a report that have more than 100 record, and i want to update them, why?  'cause i create a code in "On user input" to get the hour when someone add a new record and i put the hour in a Range of time-Field, something like this:



but i need to implement this in the records Which were previously registered, im trying to create a schedule but it doesn't work and i dont know why, the function getHour(); doesnt work there? here is the code that im trying to implement: