How create playlist in YouTube applications

You can either start a playlist with a video, or from the Library tab  .

With a video:

1. Find a video you want in your playlist.
2. Tap Save  below the video to automatically save it to the last playlist you’ve saved to, or to your Watch Later playlist. A message will pop up at the bottom of your screen confirming which playlist the video was added to.
3. To change where your video is saved, tap Change on the pop up. Select from the list of your playlists where your video should be saved. 

From the Library tab:

1. Go to the Library tab  .
2. Tap NEW PLAYLIST in the “Playlists” section.
3. Select one or more videos from your recent watch history to add to the playlist.
4. Tap NEXT.
5. Give your playlist a title and set its privacy.
6. Tap CREATE.