Your question could have more info as it’s unclear exactly what you’re trying to do.
With the info provided, the simple answer to your question “how can I create a carousel for posts that will be published a month later” is to use tags and categories, depending on which carousel plugin you’re using. For example, one carousel could display the “Current” category while the other carousel displays the “Later” category.
The Post Expirator plugin is not related to your carousel; it only adds and removes posts. If you wanted to automate the process and this option is not offered by the plugin, you’ll have to use php to modify the plugin.