EB is for version 1.2 of RTW (ie pre-BI). It has its own sub-forum here in the Org and a website (europabarbarorum.com) which will have download links. It's a brilliant mod, but only a beta so you may encounter issues (crashes to desk top etc). Another excellent mod is Rome Total Realism (RTR, which has its own website rometotalrealism.org).

I hope and expect both mods will eventually convert to the latest version of RTW, but for now your best bet is to install RTW afresh, patch to version 1.2 and - if you have space - copy the whole thing. Install a mod on the copy and retain the original for the vanilla game. I have three copies of the game on my computer - one for EB, one for RTR and one for BI.