You can add the products manually to show as recommendations.

Display the related products based on various conditions like same collection, tags, vendor & type

Shows the relevant products inspired by users browsing history

Display previously purchased items

Display recommendations based on previously purchased items

Shows the recently viewed products which were browsed by visitor

Shows the Newly added products from store

Shows products which were sold most no. of times or the best sellers by A.I.

You can assign products to a collection and select that here to show Featured Products