Update content/en/docs/concepts/extend-kubernetes/api-extension/_index.md

Co-authored-by: Tim Bannister <[email protected]>

Author: pegasas

content/en/docs/concepts/extend-kubernetes/api-extension/_index.md

@@ -5,7 +5,9 @@ weight: 30
 
 Custom resources are extensions of the Kubernetes API. Kubernetes provides two ways to add custom resources to your cluster:
 
-- The [CustomResourceDefinition](/docs/tasks/extend-kubernetes/custom-resources/custom-resource-definitions/)
-API resource allows you to define a CRD object creates a new custom resource with a name and schema that you specify.
-The Kubernetes API serves and handles the storage of your custom resource. CRDs allow users to create new types of resources without adding another API server. 
+- The [CustomResourceDefinition](/docs/concepts/extend-kubernetes/api-extension/custom-resources/)
+  (CRD) mechanism allows you to declaratively define a new custom API with an API group, kind, and
+  schema that you specify.
+  The Kubernetes control plane serves and handles the storage of your custom resource. CRDs allow you to
+  create new types of resources for your cluster without writing and running a custom API server. 
 - The [aggregation layer](/docs/concepts/extend-kubernetes/api-extension/apiserver-aggregation/) sits behind the primary API server, which acts as a proxy. This arrangement is called API Aggregation(AA). To users, the Kubernetes API appears extended.