docs: expand section on triggers

content/en/docs/cli/entities/triggers/_index.md

@@ -65,6 +65,39 @@ In this example, whenever a user visits either the homepage or the
 contact page, the "SendSlackNotification" action will be triggered,
 resulting in a Slack notification being sent.
 
+### Step 3: Firing your triggers
+
+Triggers can be fired in two different ways:
+
+- With the CLI:
+
+    ```sh
+    ops trigger fire <TRIGGER-NAME>
+    ```
+
+- With the API:
+
+    ```sh
+    curl -u $AUTH https://{API_HOST}/api/v1/namespaces/{namespace}/triggers/{triggerName}
+    ```
+
+    `API_HOST` is your Openwhisk url (`ops debug apihost`), `namespace` can be `_` to
+    use your default namespace, and `triggerName` is obviously the trigger name.
+
+    So if you create a trigger with name `event`, and you host on openserverless.dev,
+    the URL to fire it would be:
+
+    ```sh
+    https://openserverless.dev/api/v1/namespaces/_/triggers/event
+    ```
+
+    See more details in the [REST API docs](/docs/reference/references/rest_api/_index.md#triggers).
+
+> ⚠️ **WARN**
+>
+> Unfortunately, at the moment both options require authentication, which prevents
+> triggers from being used as simple web hooks.
+
 ## Conclusion
 
 Triggers provide a flexible and scalable way to automate workflows based