Add overriding Deployer variables

docs/hypernode-deploy/getting-started/install-and-configure-hypernode-deploy.md

@@ -47,3 +47,14 @@ More configurations can be found at:
 ```
 
 In the next step we're going to configure a CI/CD pipeline to let Hypernode Deploy execute the `deploy.php` configuration.
+
+## Override Deployer variables
+
+Some varaibles are automatically set, for example the default timeout of every task, you can change this by simply adding a `set` in our `deploy.php` as can be shown here:
+
+```php
+use function Deployer\set;
+
+// Change the default timeout from 300 seconds to 900 seconds
+set('default_timeout', 900);
+```