Merge pull request #61528 from gwynnemonahan/OSSM-3988

OSSM-3988: [DOC] Update cert-manager procedure intro for installation and verification

Author: abrennan89

modules/ossm-cert-manager-installation.adoc

@@ -6,7 +6,7 @@
 [id="ossm-cert-manager-installation_{context}"]
 = Installing cert-manager
 
-To install cert-manager, follow these steps:
+You can install the `cert-manager` tool to manage the lifecycle of TLS certificates and ensure that they are valid and up-to-date. If you are running Istio in your environment, you can also install the `istio-csr` certificate authority (CA) server, which handles certificate signing requests (CSR) from Istio proxies. The `istio-csr` CA delegates signing to the `cert-manager` tool, which delegates to the configured CA.
 
 .Procedure
 
@@ -195,7 +195,7 @@ spec:
 
 .Verification
 
-To verify cert-manager is installed, follow these steps:
+Use the sample `httpbin` service and `sleep` app to check mTLS traffic from ingress gateways and verify that the `cert-manager` tool is installed.
 
 . Deploy the HTTP and `sleep` apps:
 +