The Sort Orders feature uses the Algolia InstantSearch's sortBy widget (https://www.algolia.com/doc/api-reference/widgets/sort-by/js/) to display a list of indices, allowing a user to change the way hits are sorted (with replica indices).
Because Enabling this feature on your collection page requires the use of Algolia's default Sort Orders feature from the Algolia Shopify app, using this feature on your collection page without using the default Algolia Shopify app is not currently available.