Getting Started With Gutenberg By Creating Your Own Block
The plugin in question — the one we are going to go through is already published to the WordPress repository.
Please install the Testimonials Slider Block plugin to your local WordPress instance so that you have a feel for how the plugin works.
You can also fork or clone the project from GitHub.
After activating the plugin, you can go to your Gutenberg Editor and add a Testimonials Slider to your content: