The Bolt IoT App is only meant to allow you to have your Bolt connected to the WiFi. As such the Bolt IoT App currently does not have any views that allow you to control an LED connected to the Bolt.
You can control an LED by setting the pin to which it is connected to HIGH or LOW, using the remote API.
You can read about the API calls in the following link.
These API calls can be made from any browser, even the one on your Phone. In this manner you can control the LED connected to the Bolt from your phone.