README: Add validate and gather examples

README.md

@@ -56,6 +56,25 @@ Create a configuration file for Regional DR test environment:
 $ ramenctl init --envfile ramen/test/envs/regional-dr.yaml
 ```
 
+Validate the disaster recovery clusters and create an HTML report:
+
+```console
+$ ramenctl validate clusters -o validate-clusters
+```
+
+See the [validate documentation](docs/validate.md) for application validation
+and report details.
+
+Gather diagnostic data for a protected application:
+
+```console
+$ ramenctl gather application --name appset-deploy-rbd \
+    --namespace argocd -o gather-appset-deploy-rbd
+```
+
+See the [gather documentation](docs/gather.md) for output layout and secret
+sanitization details.
+
 Run disaster recovery tests:
 
 ```console