Pre-scheduling a post?

My apologies, first, if this is already posted elsewhere. I didn’t know what search keyword combo would help me find an answer… so I’m just asking anew.

Here’s the question… I’m a relative WordPress newbie. So when noticed the calendar option on the “Write posts” page, I was thrilled. I figured, this means I can write a post and then pick a date on the calendar for it to be automatically published… yes?

So I spent an hour or two picking out content of mine to publish, and gave each a date and time. Then I saved the posts as “unpublished” but with those dates in the calendar. It seemed good to go, but I just noticed that the first in the series never went up. I had to go in and hit “publish” manually.

Am I misunderstanding this feature… or possibly doing something wrong? Maybe there’s a plugin that would make it easier. All I want to do is write the posts in advance and then have WordPress pop them into place automatically, per the date and time I select.

Any tips much appreciated.

John F.