The option only works with All the Products or Specific Collections.
If you chose Specific Products in the first step, the auto-processing option is turned off and the wizard shows: Auto-processing new products is not available when selecting specific products. Choose "All Products" or "Specific Collections" to enable this feature.
Why
A list of hand-picked products cannot include products that do not exist yet. Auto-processing needs a rule that new products can match: the whole store or a collection.
What to do
- Go Back to Let's Get Started and pick All the Products or Specific Collections.
- Use the vendor filter if you only want new products from one brand.