Using the LinkedIn Learning membership provided to you by Seton Hall University, you can enroll in their "Getting started with R for Data Science" for free to learn the fundamentals of programming in R, wrangling, visualizing, and modeling all in R.
Posit Cheat sheets to make it easy to use popular packages for data analysis like Shiny, Sparklyr, ggplot2, dplyr, and more. New cheat sheets are added from time to time.
For R users that have a good grasp of the fundamentals in R, below is a link to learn more advance features in R like functional programming, metaprogramming, performant code, and more.
Posit Rstudio offers professional training courses to help users learn R independently or enroll in their RStudio Academy, and provide supplementary resources with many available for checkout in the Walsh Library.
w3school has a link to learn R programming language with tutorials to learn the basic functions, R data structures, R graphics, R statistics, and examples.