Hover your mouse over a post you want
Choose Approve/Reject
In the editing window, click on 👍 Approve
The post will now be saved as a post and scheduled for publishing at the time you chose.
Alternatively, the post will also be scheduled for publishing if you click Save changes > Publish with scheduled time Here, you can also add changes and edit the post however you want.
For approved posts, only one person (including the author) needs to approve the post for it to move to the Scheduled status.