Every hour the workflow reads the rows of a Source tab in Google Sheets and keeps only the rows whose Last changed time falls in the previous hour. Those rows are upserted into an Airtable table, matching on the ID field, so existing records are updated and new ones are created.

After the upsert, each row is written back to the sheet with a Synced at time. Because the filter looks back one hour, a row is picked up once for each change, and a row that has not changed is left alone.