For specific requests and FAQ's, it is best to search google for your question. The links below are common to come up as suggestions for your query. If you see these links as options, they are often reliable. They typically include sample code and a variety of different answers.

https://www.r-bloggers.com/https://stats.oarc.ucla.edu/r/faq/

I believe that practice is extremely helpful in becoming an experienced programmer. Below include some links where you can work on practice questions and view the solutions.

https://www.r-exercises.com/start-here-to-learn-r/http://r-tutorials.com/category/exercise-database/

Lastly, There are many free resources that you can use for further learning.