1.1 R and RStudio
This book is about using R (R Core Team 2022) to do regression, not a book about learning R itself. The text assumes you have some basic familiarity with R and RStudio (an integrated development environment for R, making using R much easier), although you do not need to be an expert by any means. See RStudio Education for Beginners for links to installing R and RStudio and for excellent learning resources.
After you install R and RStudio, install some packages that will be used in this text.
References
R Core Team. 2022. “R: A Language and Environment for Statistical Computing.” www.R-project.org.