For samples, documentation, and usage information, please see http://ehcache.org.
We released 3.1.4 on February 27th 2017.
The release notes contain the links to the artifacts and the documentation to help you get started.
You should consider upgrading to 3.2.x as it does all 3.1.x does and more with a fully compatible API.
We are now working on the missing features of the clustering tier of Ehcache 3 which will be included in upcoming 3.x releases. There will no longer be any release on the 3.1.x branch.
See the milestones on GitHub for more details on the current status.