Drupal’s core node publishing functionality lacks a feature that you may expect, if you’ve used WordPress: it can’t publish nodes in the future. While you have the option of specifying a publication date other than the current date, if you have the “Published” check box checked when you save the node, Drupal will publish the node now, listing the future date. Relatedly, if you create a node with the intent to manually publish it in the future, uncheck the “Published” check box, and save it, when you come back to the node at the intended future time, you’ll need to manually change the publication date from the time it was created to the current time, otherwise it will be published with the timestamp from the very first time you saved it.

The Scheduler module addresses the publication of nodes at a future date and time. There’s good documentation for it, as well as links to screencasts with instructions.