Every Bokeh application has a structure to it. This structure helps break the large application down into smaller components that can be built individually and then put back together to render the application as a whole. This structure is illustrated here:
As depicted in the diagram, the first step to building an end-to-end application in Bokeh is to create the plots and widgets that you would like to see in your application. CREATING PLOTS & WIDGETS is a concept that you should be comfortable with at this stage.
The next step is to DEFINE CALLBACK FUNCTION. The callback function is simply a function that tells the application how to respond when a user interacts with your application. For example, if you create a button called Update Plot, the function will update the plot with new data that it retrieves from the web. In other words, the callback...