How to draw a block diagram of a music call on the PIC16F628A

The main components of your product are applied to the structural diagram and the connections between them with the indication of the purpose (input or output) of the connections are usually arrows. Elements are indicated either in the form of geometric shapes (triangles or squares) indicating the purpose of the elements. Some elements such as speakers can be indicated by a conventional graphic designation (not a square, namely in the form of a speaker). What exactly do you not understand?