In front is a guy singing and playing guitar and a white shirted drummer in the back.
There are people making music.
A guy singing and one drummer, are people, they are playing the guitar and drumming, which is making music.
A guy singing and playing the guitar with a drummer are people making music.
The term "people" indicates that there are more than one person, and sentence one describes two men. The men in sentence 1 are playing musical instruments and one is described as a drummer, so it can be concluded that they are making music.