[narimiran]

It depends on your background.

If you would like to go from the very beginning (no or minimal programming experience): https://narimiran.github.io/nim-basics/ (disclamer: I'm the author of that tutorial)

If you are more experienced, and you want to explore all the possibilities that Nim provides, check the language manual: https://nim-lang.org/docs/manual.html

If you need any help with getting started, join Nim channel on IRC/Gitter and ask the questions. The community is very friendly and helpful! (It is one of the main reasons I kept using Nim in my Nim beginnings)