Scrow over the arrow in the bottom right hand corner and a box with smaller boxes in it will apper. Click on the box with the smaller boxes in it. then in the search bar type Tidal energy and then search. click on the video that is 4:44 and called Tidal Energy Pty Ltd and enjoy. It will show you bassically what a tidal turbine does. Feel free to check out any other videos that come up! :)