additional intro info by Roman

Author: bc-traciporter

docs/storefront/graphql/data-events.mdx

@@ -6,7 +6,7 @@ This API is particularly useful for tracking analytical metrics, including visit
 
 ## Introduction
 
-A fundamental concept in BigCommerce analytics is the "visit" or "session". When sending events to BigCommerce you must include a `visitId` and `visitorId`, both formatted as UUID. You can generate these values using the [UUID Generator](https://www.uuidgenerator.net/version4). The following steps, along with an example for enabling a headless storefront, are described below.
+A fundamental concept in BigCommerce analytics is the visit details. When sending events to BigCommerce, you must include a `visitId` and `visitorId`, each formatted as a UUID. The `visitId` represents a session within the data pipeline, while the `visitorId` identifies a visitor or shopper. The `visitId` is typically stored in a short-lived cookie. In Stencil, its default time-to-live (TTL) is 30 minutes and we recommend using the same TTL for headless stores. In contrast, the `vistorId` is assigned to a shopper and has a TTL of one year in Stencil. You can generate these values using the [UUID Generator](https://www.uuidgenerator.net/version4). Below, we outline the steps for enabling a headless storefront, along with an example implementation.
 
 ## Enabling a headless storefront