To use your template in your playlist, you have to add it to your media library as a new slide. Therefore click the "Media library" button in the main menu on the left. Click on the button “Add” and select the option "Create from Template". A window will open where you can add a template with a double-click.
If there are placeholders in your template, a new window will open. There you can fill the placeholders with media files and text.
Click "Save" and you created content from your template that you can use in playlists.