First off, I am going to tell you this technique is tricky to master. That said, with some patience, midday sun and some good tinder material such as the char-cloth used in the video, this can be done.
As with all fire starting techniques it is vital you are patient and know exactly what you are doing. Rushing things or skipping steps will only result in frustration and failure. Learn the technique and take your time with the process.
Also check out: How To Make A Bow Drill & Start A Fire (With Ray Mears)