A shiny application typically includes a folder with the ui.R and server.R files. The code in ui.R controls the user interface, and server.R controls the data that the application renders on the user interface, as well as how the application responds to user actions on the interface.
In step 1, the dummy application presents a simple static user interface with no scope for user interaction.
The shinyUI function of ui.R constructs the user interface. In DummyApp, the function constructs the user interface with three static elements. It uses the pageWithSidebar function to create a page with static text in headerPanel, sidebarPanel, and mainPanel.
The shinyServer function in the server.R file controls how the application responds ...