The answer on the "how to join" question depends on the particular situation at your institution and the software you use for managing student mobility. Please read below which situation fits for your own institution.

You can also have a look at some instruction videos on how EWP works.

AtĀ  the moment EWP is inviting HEIs with their own SIS to start up a testing EWP implementation. More info can be found here.

The EWP Network will hold it launching conference on the 12th and 13th of December at Ghent University (Belgium). Information about the conference is available here.