I think this will be very simple exercise. Material for this section is quite identical to previous Creating Interactive scene tutorial. But, notice that transition between 'walk' and 'jump' in that sample happens abruptly.
To create smooth transitions between motions instead of
var nc:NavigationController = new NavigationController(node,"navigator");
we need to use
var nc:NavigationBlenderController = new NavigationBlenderController(node,"navigator");
everything else is absolutely the same:
Full source code is available here.
also here is demo sample.