Here is a webpage that can get you started with contour plots: https://plotly.com/r/contour-plots/.
There are many free R books online that can teach you programming in R. I do not know about any for climate data however many of the same data analysis concepts should apply across different fields.
In addition to the excellent comments of respected professors , this pdf file i will share is about Contour Plot. it's 5 pages that has R codes about contour and also examples and description about arguments. Maybe it will help you.