To add Sublist Action Group in workflow,
- Open the respective workflow, where sublist action group to be added.
- Double click on the respective state
- New window opens, click on New Sublist Group

4. Add required fields and condition if necessary.
5. Select “Items” from sublist under parameters tab and click Save

6. Again, double click on the state and select the respective Sublist Action Group

7. Click new action and select required action.
8. Add necessary fields and save.