Almost everything with a public face in this CMS is draft-enabled: pages, articles, products, categories, career positions, and the single pages like the home page and the 369 page. The mechanics are identical everywhere, so they live on this one page.
A new document is a draft: fully editable, saveable, and invisible to visitors. The same applies after publishing, edits save as a new draft on top of the published version, and the live site keeps showing the published one until you publish again. You can polish a page over a week of saves and nobody sees a thing.
The admin always shows the newest draft, the site always shows the last publish. When those differ the document's status shows it has unpublished changes.
Publish makes the current draft the live version. Unpublish pulls a document off the site without deleting anything, it goes back to being a draft and can be published again later.
Next to Publish sits the schedule option: pick a date and time and the current draft goes live on its own. Useful when a campaign has to start at midnight without anyone being awake for it. Scheduling works per document, so a new page, a home page swap and a price-drop article can each carry their own go-live moment.
Schedule the version you would happily publish right now. Whatever the draft looks like at the scheduled moment is what goes live, so keep half-finished edits out of a scheduled document.
The system keeps the last 20 versions of every document. The Versions view shows them with timestamps, and any of them can be restored, which brings the old state back as a draft for you to review and publish. A botched edit is never more than two clicks from undone.