.When you see a youtube video, you will see a "+" sign on the bottm left-hand corner. Click on that sign once, and it will store that video in your quicklist. Keep doing that to the videos that you want to watch. When you are done selecting the videos you want to watch, look in the upper portion of the youtube page. There it says "quicklist" and shows in the brackets how many videos you have quicklisted. Click on "quicklist" and you will see that it will ask you if you want to watch them individually or play all. Click "play all" option and you're done.
Remember, the quicklist that you create this way is lost if you close your browser. So if you want to watch the videos in your quicklist after a short cigarette or tea break, don't close the browser.