Nothing goes out on a new Series until you've seen it. The first post always waits for your approval, so you can check the look and the sound before the schedule starts.
Approve a post
Open the post. You can reach it from the Needs approval post under Up next on the Series page, from its card in the Studio, or from the notification and email that tell you it's waiting.
Check it in the editor. Change the visuals, music or text if you want to.
Choose Approve and publish, then confirm.
The project exports to a new video and publishes it to the Series' channel. If you approve before the posting time, it goes out at that time. If the posting time has passed, it goes out as soon as the video is ready.
Changes you make in the editor stay in the project, so later posts start from them. Making a new picture, clip or track there uses usage, the same as in any project.
After the first post
Later posts follow the Before each post publishes choice you made when you created the Series:
Auto-publish: every post goes straight to YouTube at its posting time. It's fully hands-off.
Manual approval: every post waits for you, and you approve each one the same way.
While a post is waiting, the Series makes no new posts. Each posting time that passes in the meantime is skipped, so approve the waiting post to keep the schedule going.
The Series page doesn't let you switch between Auto-publish and Manual approval later. A connected agent can change it for you.
If a post seems stuck, Why a scheduled post was skipped has what to do. Anything else, email [email protected] and a person will read it.