To learn R for Data Science, starts with learning the basics of R like data types, operators, variables, functions, loops, and conditional statements. After that, learn how to create, append, subset datasets, and analyzing data. After that, learn using the ggplot2 package to create histograms, line charts, bar charts, scatter plots. Also, learn to do hypothesis testing using R programming. Then, learn to build statistical modeling like linear regression, logistic regression, clustering.
I would recommend this Data Science with R Course by Intellipaat to speed up your learning process.
You can watch this video to get started with Data Science with R: