Tutorials for Bb are everywhere. Usually you can google Blackboard tutorials and find what you need.

http://www.utexas.edu/academic/blackboard/tutorials/ is the link to tutorials from UT-Austin. This is a fairly comprehensive collection of tutorials that I thought you might find helpful at some point.

http://www.clt.odu.edu/bb/index.php?src=tutorials is from Old Dominion University. This is one that has a large amount of Flash tutorials if you like animation.

http://facit.cmich.edu/workshops-training/blackboard/tutorials.html is from Central Michigan University and features Flash tutorials. Some have PDF versions for printing.