Finding the right resources to learn R on the internet can be tricky. Here are two that I've found to be useful:
R Bootcamp: From Jared Knowles, a political science graduate student at the University of Wisconsin Madison. If you want to learn R quickly while still learning pretty much everything you need to know, this is a good option. The tutorial will be a bit difficult to understand if you don't have a background in statistics and/or computer programming, but it is not so jargon-filled that you won't be able to understand it if you are just a beginner. Another positive about this course: it uses RStudio, a graphical user interface (GUI) that is very intuitive for beginners.
Introduction to Probability and Statistics Using R: A much more comprehensive tutorial created by G. Jay Kerns, a professor at Youngstown State University. About 400 pages long, this tutorial is for those wanting a comprehensive introduction to R. In spite of its length, I think that the language used is easy-to-understand, even for those without a background in statistics or programming.
Note that there are many other free resources available, such as the Springer textbooks Use R! and Introductory Statistics with R. If you have more time and are interested in a class-like structure, you could also take a basic statistics course at Coursera, or one at edX (most of them will require R).
In addition, here are some other resources you might find useful:
Introduction to Data Technologies: This is not exclusively for R, but there is a chapter on using R to manipulate data. This is most useful (or at least it was most useful to me) as an introduction to using regular expressions in R.
Quick-R: Good to use as a reference guide. Look up a topic you're interested in if it wasn't covered in the tutorial you're going through.
Stackoverflow: A good place to ask questions. Do a search first to make sure that nobody else has asked your question already.