Hi Jordijuanola,
1. The playlist will be available only in the latest version 3.0, hence please download the latest version and install it, so you can go to admin -> Video Gallery -> Playlist to create playlist.
2. Ensure you have applied YouTube API key in the settings. Go to Admin -> Video Gallery -> Settings -> YouTube API key -> Enter and save the settings.
To create YouTube API follow the steps provided below
1. Go to the Google Developers Console and Select a project.(https://console.developers.google.com/
project).
2. In the sidebar on the left, select APIs & auth. In the list of APIs, make sure the status is ON for the
YouTube Data API v3.
3. In the sidebar on the left, select Credentials.
4. Here, click “Create New Key” button and it opens one dialog box. In this select “Browser Key”.
5. It opens new window. Here, no need to enter any data. Click create button. It displays “API key”.
Copy the key and paste in admin -> Video Gallery -> Settings -> YouTube API and save the key.
Now go to Add videos and try adding YouTube videos. It should work.