Update subscriptions docs with 6.x changes

Author: angrykoala

modules/ROOT/content-nav.adoc

@@ -50,8 +50,7 @@
 ** xref:subscriptions/getting-started.adoc[Getting started]
 ** xref:subscriptions/events.adoc[Events]
 ** xref:subscriptions/filtering.adoc[]
-** xref:subscriptions/scaling.adoc[]
-** xref:subscriptions/engines.adoc[Engines]
+** xref:subscriptions/customize-cdc.adoc[]
 
 * *How-To*
 

modules/ROOT/pages/subscriptions/customize-cdc.adoc

@@ -0,0 +1,39 @@
+[[customize-cdc]]
+= Customize CDC Subscriptions
+:page-aliases: subscriptions/plugins/index.adoc, subscriptions/plugins/amqp.adoc, subscriptions/plugins/single-instance.adoc
+:description: This page describes how  to customize the behaviour of subscriptions.
+
+== Neo4jGraphQLSubscriptionsCDCEngine
+
+By default, the GraphQL library will use the same driver passed to `Neo4jGraphQL` to poll for events every second. This behaviour can be changed by creating a custom instance of `Neo4jGraphQLSubscriptionsCDCEngine`.
+
+The following options can be passed to the constructor:
+
+* `driver`: The driver to be used for CDC queries.
+* `pollTime`: The interval, in milliseconds, between queries to CDC. 
+Defaults to 1000ms.
+Note that poll time is the period between one request finishing and the next one starting. 
+The actual time it takes for CDC events to trigger the subscription also depend on your network.
+* `queryConfig`: An object with the driver query options to be passed to CDC requests. 
+Use the `db` field to define the target database for CDC. 
+
+For example:
+
+[source, javascript, indent=0]
+----
+import { Neo4jGraphQL, Neo4jGraphQLSubscriptionsCDCEngine } from '@neo4j/graphql';
+
+const engine = new Neo4jGraphQLSubscriptionsCDCEngine({
+    driver,
+    pollTime: 5000
+})
+
+const neoSchema = new Neo4jGraphQL({
+    typeDefs,
+    driver,
+    features: {
+        subscriptions: engine,
+    },
+});
+----
+