R is an easy programming language with a simple syntactic structure. Therefore, it is easy to learn R programming in a short time. As a beginner, you should start with the basic concepts of R programming, such as data types, variables, operators, data structures, interfaces, graphs, and statistical parameters. To learn fast, you must start working on datasets and various projects from scratch. Try to implement each concept using real-life scenarios. This will help you learn and improve to hold command over the R programming language.
If you are looking for an online course to learn R programming, check out this R Programming Certification program by Intellipaat.