diff --git a/README.md b/README.md
index b571662..ebd6e1e 100644
--- a/README.md
+++ b/README.md
@@ -1,7 +1,10 @@
 ## Usage:
 1. Create `ssl` folder to store certificates and this repository.
 2. Clone this repository or use as submodule:
-   - `git submodule add ssh://git@git.w3goodies.com:17001/mehdi-mac/certbot-docker-script.git`
+   ```shell
+    git submodule add ssh://git@git.w3goodies.com:17001/mehdi-mac/certbot-docker-script.git
+    chmod +x certbot-docker-script/generate-certs.sh
+   ```
 3. Create `certs` folder inside `ssl` folder.
 4. Put `config.sh` inside `ssl` folder.
    - Copy contents from [config-example.sh](https://git.w3goodies.com/mehdi-mac/certbot-docker-script/src/branch/main/config-example.sh)