You can download the latest version at github by clicking the .zip at top.
So how to set it up:
For the very first step you have to rename the "eXpansion-master" to "eXpansion"
I upgraded the Administators guide at our wiki, so check the wiki for example configuration file.
http://exp.tm-teams.com/wiki/doku.php?id=admin:config
You might also want to install oliverde8 hudmenu and my dedimania plugin, for the dedimania plugin you have to also rename the folder from "Dedimania-master" to "Dedimania", see the github page for configuration options.
If you install menu and dedimania, be sure to load them before eXpansion plugins

Note
There will be upgrades nearly every day to the current development version of the plugin pack. We have tested the plugin pack in production servers now for 2 months, it works pretty good and solid at the moment, but there are some optimizations yet to be done before we publish version 1.0, so remember this is still considered as a beta.
When we release, we will upgrade all administrative part of the exp wiki, so there should be better support for server admins than currently.
Hopefully this helps, if not, don't hesitate to ask.
- Reaby