Datomic can be downloaded freely from its Get Datomic (http://www.datomic.com/get-datomic.html) website. To start with Datomic, download the Datomic free edition that includes a memory database and embedded Datalog query engine. The free edition is also limited to two simultaneous peers and embedded storage that should be good enough to try out Datomic features and work with its data model.
Using Datomic
Getting started with Datomic
To set up Datomic, download and extract the free edition's datomic-free-x.x.xxxx.xx.zip file. The free version of Datomic does not require any license key. For other versions, registration is mandatory to obtain a license key which must be added to transactor properties for Datomic...