Leiningen is the easiest way to use Clojure. With a focus on project automation and declarative configuration, it gets out of your way and lets you focus on your code.
(defproject leiningen.org "1.0.0" :description "Generate static HTML for https://leiningen.org" :dependencies [[enlive "1.0.1"] [cheshire "4.0.0"] [org.markdownj/markdownj "0.3.0-1.0.2b4"]] :main leiningen.web)
Leiningen and Clojure require Java; ideally OpenJDK.
You can check your package manager as well depending on your operating system.
The tutorial is the best place to start. If you have Leiningen installed, you can read the tutorial by running lein help tutorial. It does not cover learning the language itself; good Clojure documentation can be found elsewhere.
Running lein help faq will get you the FAQ. Documentation for each individual task is available via lein help $TASK. You can also see the sample project.clj file containing a reference of most project settings by running lein help sample.
At the time of this writing Leiningen is the most widely-contributed-to Clojure project. We welcome potential contributors and do our best to make it easy to help out.
Discussion occurs primarily in the #leiningen channel on Freenode.
Issues should be reported on the GitHub issue tracker.