Who also struggles at S line part, this well explained video might help you : kzfaq.info/get/bejne/rLhdhMp0lbO7pJs.html -good luck on your road test :)
This is a very poor video in regards to looking both ways before leaving any stop line. While the video's written instructions say to do so, the rider on the track is not shown turning her head at any stopping point. Basically, you need to look both ways every time you stop or you will fail (you can forget once). A good rule is: 在停綫上准備走,一定記得先擺頭。 Or for English... if your feet are on the ground, look around. They are very strict about this. Also the test track is much smaller than I imagined it after looking at the diagrams and videos. If you have a larger bike or scooter, borrow and practice on a smaller bike; you will find it much easier as some of the turns are quite tight. I watched several larger bikes fail.