How to read csv file and plot bar chart using R Shiny Web Application

Im new to R Shiny Web Applications, so how do I read csv file and plot a bar chart using R Shiny Web Application? Let say my data file is called data.csv. I understand in order to read the csv file I have to do this:

fulldata <- read.csv(data.csv)

After which, how should i plot a bar chart? I can't use ggplot I know for sure. Given that in data.csv, there are only two columns (ID and age).