If you don't have a subscription for ChatGPT you can't use the GPT storyboarder. Nevertheless, you still can create similar storyboard like images pretty easily for free.

You can do that for example by using the Copilot app from Microsoft which gives you free access to ChatGPT 4 and Dall-E 3 (with a daily limited usage).

In copilot you can use this sentence or prompt as a starting point:

Create an image of [write your description here] 

The image is black and white with touches of red and in the style of a storyboard.

Demo