Switching over from R Markdown?
If you are an R Markdown user starting to use Quarto for your new projects or if you are converting an existing R Markdown project to Quarto, I highly recommend reading the FAQ for R Markdown Users.
You might particularly find the I use X (bookdown, blogdown, etc.). What is the Quarto equivalent? question as it provides a table comparing R Markdown outputs with Quarto formats, providing a roadmap for where to get started depending on the nature of your project.
It should also be noted that R Markdown is not going away. Quarto simply expands the scope of R Markdown, and R Markdown will continue to be actively supported.