There are a number of ways to do it:
Dissolve a black color clip on a higher track in
Dissolve to nothing (if it's just one track)
Ramp the opacity to 0 (if it's just one track)
http://www.panoramaproductions.net/edius_tutorials.htm
If you are and old Adobe user this site will give you information on how to set it up like an Adobe timeline. This is my perfered way of editing with Edius and has lots of other info about Edius.