1. Go to the 4 second mark in this video then pause it.
2. Go to the 1:25 minute mark in this second video, also at YouTube. N'Diaye Rose is holding up his fingers to signal the start of a drumming sequence. When you see him raise his third finger (1:29), return to the first video, start it, and watch. (The voices you hear briefly in the background are on the second video; ignore them.)