Reset Workbook To Original State

I am looking to create a macro button which will reset the sheet to its original state.

I have locked the cells users should not imput data into, and unlocked where they add their data.

At the end of every school year, they will need to be able to reset ALL the workbooks back to their original state with all the reference formulas.

I am thinking I will need to tell the macro to create a hidden copy of the workbooks and then upon hitting reset it will use the backup to override the current. But they will need to be able to reset at the end of every year.

I would like to have one reset button that resets ALL the workbooks at once, but if not, I could put a reset button on each workbook.

As I have just started my VBA training, I have a code that will create a backup and hide it, but I have no idea how to do the reset portion. And again, since they need to be able to reset it each year for x amount of times, I don't know how to get it to keep having a fresh backup and get everything to its original.