Add the Fade transition
Click "View Video Transitions"
Scroll down to the FADE transition
Drag that transition between the two clips
You can then, in the timeline view, click the transition to select it and
drag the left side back and forth to adjust the length/duration of the fade.
--
Wojo
MVP - Windows Digital Media
You can't "combine" them except in that they get combined when you render
the finished movie.
If you are trying to right click and then combine like you can with split
clips that will not work once a transition is placed between them.
-Wojo