How do you use sm64 rom extender?

To use the SM64 ROM Extender, first, ensure you have a Super Mario 64 ROM file and the ROM Extender tool. Open the tool and load your ROM file, then select the desired options for expansion, such as adding new levels or modifying existing files. Once you've configured your settings, run the extender to create a new ROM with the changes applied. Finally, test the modified ROM in an emulator to see your enhancements in action.