Lesson 0 - Install R and RStudio
Install R on your computer. Pick the one that fits your system (PC vs Mac; what version of Windows vs what version of Mac OS). For PC's, check if your PC is 64-bit or 32-bit before downloading R and RStudio.
Choose the CRAN location closest to you.
Then install RStudio. Again download the one that matches your computer.
Let me know when this is done or if you need help.
Watch the above video about navigating RStudio [20 min]