diff --git a/README.md b/README.md
index 4ab5e42..3059d9f 100644
--- a/README.md
+++ b/README.md
@@ -21,7 +21,7 @@ First clone the repository:
 $ git clone https://github.com/seaweedfs/seaweedfs-operator --depth=1
 ```
 
-To deploy the operator with webhooks enabled, follow the instructions in the `config/default/kustomization.yaml` file to uncomment the components you need.
+To deploy the operator with webhooks enabled, make sure you have installed the `cert-manager`(Installation docs: https://cert-manager.io/docs/installation/) in your cluster, then follow the instructions in the `config/default/kustomization.yaml` file to uncomment the components you need.
 
 Then run the command to deploy the operator into your cluster:
 
@@ -81,4 +81,4 @@ $ make run ENABLE_WEBHOOKS=false
 
 # From another terminal in the same directory
 $ kubectl apply -f config/samples/seaweed_v1_seaweed.yaml
-```
\ No newline at end of file
+```