New records will sync to Zebrafi when they are created. If you would like to sync any existing records to Zebrafi you can retroactively trigger the Zebrafi Workflow rules on current records.
1. In Salesforce, export a report (CSV) with just Ids of the records on which you want to run the workflow rule
2. Open the CSV with Excel to ensure that there are no other lines other than the Ids and the Column title (no header and footer)
3. Perform an Update with Data Loader (or any other API tool), and map only the Id of each record