How does the queue work?

Each channel has times in the week when its queued posts go out. Until you set your own, they're 9:00 am, 12:30 pm and 5:00 pm every day, on your workspace's clock.

Add to queue gives each channel its next free time. Change a channel's times under Posts, then Posting times. Posts already scheduled keep their time.

The Calendar shows every channel's posts week by week. Open one to change it, put it back in drafts, or discard it.