Here are a few external links to get us started. If you find other helpful resource, please let me know.
A. Installations and Basics
1. Installation and Basics, R Studio (via UCLA)
2. Basic Tutorial (Installations, functions, commands, and a whole lot of things!)
B. Graphs and Visualization
1. Basic Graphs in R (via DataCamp)
2. Guide to get started (and more) with ggplot2 (via Selva Prabhakaran)
3. Adding Confidence Intervals on plots.
C. Some structured resource (via Jennifer Bryan): https://happygitwithr.com/index.html
D. R Markdown
I've used R Markdown to make some of my slides. It is a neat package that allows you to embed and run your codes and print results in your slides. And you can also write papers, etc. I've used it to write the replication codes for the chapters. Here is a good place to start: https://bookdown.org/yihui/rmarkdown/markdown-syntax.html (via Xie et al.) and https://help.github.com/articles/basic-writing-and-formatting-syntax/#headings(via GitHub).
E. R bookdown
R bookdown essentially combined Markdown features to publish in a book format. I will be using bookdown to write/publish my dissertation. More information coming soon. Helpful link: https://bookdown.org/yihui/bookdown/