1. Use as a trigger the time intervals so you can run this process automatically every morning at 7 am
2. Add action find with condition the records you want to process in you update. Based on your description you could add all records from a view with no filters because you want to clear all records form your base. 😉
3. Choose "Repeating group" so the next actions will run for each record from Find action.
4. Create Update record by adding the following setting:
* record id = > current item - record id
* long text => add it in the list of fields you want to update and just leave it empty
* Check box => leave it unchecked.
For any kind question please feel free to to text on airtable commuity 🙂