1. Click "Products"

2. Click "Collections"

3. Click "Create collection"

4. Click the "Title" field.

5. Enter the desired name of the collection

6. Click Automated.

7. Click any condition.

8. Click the "Condition 1 value" field and enter the name of the sub-collection you want to include

9. Click "Add another condition"

10. Repeat steps 8-9 as needed until you have all relevant sub collections

11. Click "Save"