Product Filter & Search helps your customers find the exact products they want within seconds by providing fast navigation to the products with multiple filtering options, smart search & suggestions, and with just one-click install! 

Integrating Product Filter & Search and will allow you to create a filter option by reviews, in order to do so, you have to:
1. Install Product Filter & Search on your Shopify Store Dashboard and the app will walk you through on boarding process

2. On your app admin, go to Settings> Integrations> Storefront> Search and click on Product Filter & Search. You will be redirected to Product Filter & Search help desk article "Step by step instruction on how to integrate with app"