Sure, I'd be happy to help you understand YouTube playlist functionality.

A YouTube playlist is a collection of videos that can be viewed sequentially and shared with other users. While any user can create personal playlists of videos for their own use, creators can also build playlists on their channels for their audience. Here's how it works:

1. **Creating a Playlist**: You can create a playlist while you're watching a video. Below the video, click "Add to" and then click "Create new playlist." Enter a playlist name, choose its privacy setting, and then click "Create."

2. **Adding Videos to a Playlist**: You can add a video to a playlist while you're watching it (same as above), or you can add it from the video's YouTube page. Just click "Save" below the video and select the playlist you want to add it to.

3. **Managing a Playlist**: You can manage your playlist by going to "Library" in the left-hand menu, then selecting the playlist you want to manage. Here you can change the order of videos, remove videos, change the playlist's privacy settings, and more.

4. **Sharing a Playlist**: If you want to share a playlist, go to "Library," select the playlist you want to share, then click "Share." You can share it on social media, in an email, or by copying and pasting the playlist link.

5. **Watching a Playlist**: When you watch a playlist, the videos will play in the order they're arranged in the playlist. You can also shuffle the playlist or loop it.

Remember, the privacy settings of a playlist are as follows:
- **Public**: Anyone can see and share your playlist.
- **Unlisted**: Only people with the link can see your playlist.
- **Private**: Only you can see the playlist.

I hope this helps! Let me know if you have any other questions.