Pull the Rudder Deployment Cable (black thick rope) toward the bow by grabbing the red Rudder Deployment Ball, which will provide extra grip. Ensure that the Deployment Cable is not in the Rudder cable cleat while pulling. Once the Rudder Blade is fully deployed, only then can you slot the Rudder Deployment Cable into the rudder cable cleat to keep the Rudder Blade in place.
Friendly-tip: The easiest way to deploy the Rudder Blade is to pull the Rudder Deployment Cable in one strong motion instead of pulling it slowly.