The entity store was released a while back as a hotfix and is included in CU11 for AX2012 R3. You can read more about it in this post and white paper. While there are a few notes in the white paper they aren’t that detailed on how to setup the entity store.
There are a few things that you will need to plan and do. First is where to store the data. Essentially the entity store is an extraction of data from the AX database to another database that you could consider as a data warehouse. The structure of the data that is moved over there is dependent on the data entity seeing this is built on DIXF. So if they entity only has one table then that is all the data that is moved, if the entity is complex, in that it joins a few tables, then you will end up with one table in the entity store as demoralized data. This is helpful for reporting because whoever needs to consume the data doesn’t have to do the joins as that work will have been done when the data is moved over to the entity store.
Here is a quick overview of how to setup the entity store
AX2012 R3 CU11