The actual vignettes were accompanied by recorded music, but at the beginning of the evening we were given a demonstration of percussion, stringed, and wind instruments. You can see the demonstration in the video. Which ends with part of the first opera vignette where you can see and hear the use of the percussion instruments.
For more, Philmulti gives a nice overview of Chinese traditional stringed instruments with pictures and a video.
From a post on a Chinese music forum:
Music accompanies singing. reciting. actions and acrobatics in Chinese operas. It also helps develop the story. personalize the characters. expose their thoughts and feelings. and create a special atmosphere.
The orchestra of a typical opera is composed of two parts -- the Wenchang. or Civil Section. of string and wind instruments; and the Wuchang. or Military Section. composed of percussion instruments. The former section accompanies singing. and the music is Qu (tunes). The latter accompanies the performers` body movements. reciting. singing. dancing and acrobatics.
The beats clearly mark the beginnings and the endings. Led by the main drummer. the music adjusts and controls the rhythm of the opera. The instrumental music is produced by various kinds of stringed. wind and percussion instruments. and each has its own functions and timbres.