update permissions doc

Author: lucasfernog

src/content/docs/plugin/biometric.mdx

@@ -180,8 +180,18 @@ try{
 
 ## Permissions
 
-By default all plugin commands are blocked and cannot be accessed. You must define a list of permissions in your `capabilities` configuration.
+By default all potentially dangerous plugin commands and scopes are blocked and cannot be accessed. You must modify the permissions in your `capabilities` configuration to enable these.
 
-See [Permissions Overview](/security/permissions/) for more information.
+See the [Capabilities Overview](/security/capabilities/) for more information and the [step by step guide](/learn/security/using-plugin-permissions/) to use plugin permissions.
+
+```json title="src-tauri/capabilities/main.json" ins={6}
+{
+  "$schema": "../gen/schemas/desktop-schema.json",
+  "identifier": "main-capability",
+  "description": "Capability for the main window",
+  "windows": ["main"],
+  "permissions": ["biometric:default"]
+}
+```
 
 <PluginPermissions plugin="biometric" />