To use comments on your static website you need a way to process those and keep them updated on your static website. This is where these settings com to play.
First, you can decide if or not you want to use comments on your static website. Then you have to add an endpoint to process new comment submissions. You can do that with external services or use your original WordPress website to do that for you.
Simply Static includes a webhook called “comment” for that. Every time a visitor submits a comment on your static website, it will be sent to the shown endpoint and a function gets triggered to add that comment to your WordPress admin area.
Immediately after that, Simply Static will export a new static version of the post/page where the comment was made and it should be visible a couple of seconds later (depends on your configuration and server environment).
In most cases you have to configure the CORS settings to allow the submission from another domain.
You can also configure a redirect URL after a comment was added. As the static page doesn’t get a response from the callback this is highly recommended to keep the user informed that the comment was added successfully.