Apply suggestions from code review

Co-authored-by: Misha <misha.kotov@gmail.com>

Author: erikmarr

src/recommendations/headless.md

@@ -4,18 +4,34 @@ title: Integrate Product Recommendations into your Headless Storefront
 ee_only: True
 ---
 
-You can integrate Product Recommendations in a headless storefront using either [PWA Studio](https://magento.github.io/pwa-studio/) or another frontend application, such as Next.js.
+You can integrate Product Recommendations in a headless storefront using either [PWA Studio](https://magento.github.io/pwa-studio/) or a custom frontend technology, such as React or Vue JS.
 
-If using another headless storefront, you use the Commerce Storefront SDKs to send or request data. These SDKs allow you to control the storefront event publishing, collecting, and fetching.
+Product Recommendations require [behavioral and catalog data ](https://devdocs.magento.com/recommendations/product-recs.html#types-of-data)to operate. The catalog data sync process remains unchanged in a headless implementation, but changes are needed for behavioral data collection. 
 
-Use the following workflow to attach your headless storefront to the Product Recommendations backend.
+The roles of the custom storefront using Product Recommendations are two-fold: 
+1. send behavioral data to Adobe Sensei so that these events can be analyzed to compute Product Recommendation results; additional data can be sent to enable product recommendation [metrics reporting](https://docs.magento.com/user-guide/marketing/recommendation-metrics.html) 
+2. fetch product recommendation results and render them on the page 
+
+Both of these actions can be performed using available SDKs as described below. 
+
+Use the following workflow to integrate your headless storefront with Product Recommendations.
 
 1. [Install the Product Recommendations]({{ page.baseurl }}/recommendations/install-configure.html) module.
 
-1. Install and use the [Storefront Events SDK]({{ page.baseurl }}/shared-services/storefront-events-sdk.html) to trigger the behavioral events.
+1. Install and use the [Storefront Events SDK]({{ page.baseurl }}/shared-services/storefront-events-sdk.html) to fire the [behavioral events](https://devdocs.magento.com/recommendations/events.html).
+The minimum required events to enable product recommendations are product view, add-to-cart, and place-order. 
+To enable metrics reporting (link), the following additional events are required: 
+recommendation-unit impression-render
+recommendation-unit view
+recommendation-unit rec-click
+recommendation-unit rec-add-to-cart-click (if an add-to-cart button is present in the Recs template) 
+--
+
+
+<br class="Apple-interchange-newline">
 
-1. Install and use the [Storefront Events Collector]({{ page.baseurl }}/shared-services/storefront-event-collector.html) to send those events to Adobe Sensei.
+1. When the events are fired, use the [Storefront Events Collector]({{ page.baseurl }}/shared-services/storefront-event-collector.html) as a handler to send them to Adobe Sensei.
 
-1. [Create Product Recommendations](https://docs.magento.com/user-guide/marketing/create-new-rec.html) in the Commerce Admin.
+1. Once behavioral data collection is orchestrated using above steps, the business user can [create Product Recommendations](https://docs.magento.com/user-guide/marketing/create-new-rec.html) in the Commerce Admin.
 
-1. Install and use the [Recommendations SDK]({{ page.baseurl }}/recommendations/recs-api.html) to fetch the recommendation units on the storefront.
+1. Use the [Recommendations SDK]({{ page.baseurl }}/recommendations/recs-api.html) to fetch the recommendation units on the storefront. It returns necessary product data to render recommendation units on a page.