Shiny file upload demo

server.R

shinyServer(function(input, output) {
  output$filetable <- reactiveTable(function() {
    if (is.null(input$files)) {
      # User has not uploaded a file yet
      return(NULL)
    }
    
    input$files
  })
})

ui.R

shinyUI(pageWithSidebar(
  headerPanel("File input test"),
  sidebarPanel(
    fileInput("files", "File data", multiple=TRUE)
  ),
  mainPanel(
    tableOutput("filetable")
  )
))

Dear,

I am new to R-shiny, Can you please help me "how to create a graph using the file which user loaded manually through fileinput function.?
Basically i would like to access the variable from the file loaded by user and create a graph