Here http://ez.no/download/ez_publish/ez_publish_4_stable_releases/4_0/packages/4_0_0 you can download all the packages related to eZ Flow (if you already have installed ezwebin, you can skip it):
* ezflow_extension
* ezwebin_extension
* ezflow_classes
* ezflow_democontent * ezflow_design
Then you can import these packages in your existing eZ Publish 4.0 site (eZ Flow is built to work only with this version).
