Depends on what you have available.
I empty the frames of honey or unripe honey. Then I wrap them in Cling Plastic Wrap (from CostCo) and freeze them for at least 48 hours. That kills off any wax moth and SHB larvae/eggs/pests. If you have space, just leave them in the freezer until next March, then get them out, defrost, wash out the drainage channel with warm water and put them back on the hive. Don’t wash off the wax etc, it is bee-friendly and will encourage them to use the frames faster next year.
If you can’t store them in the freezer, freeze them first anyway, then put them back into a super with several layers of burlap above and below it to allow air circulation, but keep out small insects. Store in a cool dry dark place (garage is fine) until next season.
Next year, you might benefit from joining a local club and getting a mentor. Tell them you have an 8-frame Langstroth hive (don’t mention Flow to start with) and they will likely help you a lot.