All Checkstyle Addons downloads are now via Maven Central. Since we have quite a lot of files there, this pages tries to describe all of them briefly.
The most important factor is the Checkstyle version that you use:
As always, choose one version of Checkstyle and stick with it. Checkstyle versions are usually not compatible with each other, so your choice of plugins and the contents of your checkstyle.xml depend on the particular version of Checkstyle.
Find detailed descriptions on how to set things up on the Get Started page.