Graphing in R will be crucial in your data science work, and we have covered most of the basics here. However, graphing is one of those things where, most of the time, there are always going to be different types of graphs you haven't heard of yet and options you haven't yet selected, so it's important to know where to look for assistance and how to keep learning.
We have only covered the basics to get you off the ground in ggplot2 in this book, so you'll definitely need to use Stack Overflow and the ggplot2 official documentation on the Tidyverse website to experiment with different graphs and aesthetics. You should look into how to use scales, how to have ggplot2 calculate statistics for you, and the many other different types of plots available.
Let's press forward on to the next topic, where we'll begin to look at some data more...