If you have never worked with R, you can get a basic familiarity by going through this free tutorial. Takes about 4 hours.
You can also learn R straight from within R using the swirl package. This doesn’t require internet access except to install the package.
Here is another basic R introduction from ComputerWorld.
The book that I recommend for scientists who have never worked with R is The R Student Companion by Brian Dennis. It’ll get you up to speed with the type of programming that scientists do with R. I think you’d be fine just renting it for a month and getting through as much as you can in a month. After a few chapters, you’ll know your way around R and, more importantly, how to program with functions. Then you’ll be ready for something else.
Once you work through that, R for Data Science by Garrett Grolemund and Hadley Wickham is very good for what the sort of work we do.
These are some basic packages that I use all the time. This does not include the analysis packages that I use.
readHTMLTable() function. I think xml2 in the tidyverse might do the same thing.file.path() allows you to make file paths to the base of the project. If you find yourself doing setwd() anywhere in your code, you’ll want to use here() to avoid that because doing that breaks your code for anyone else.