Start here...
http://home.att.net/~thetandemlink/LearningCenter.html

Although not as detailed as "The Tandem Scoop" that used to come with Burley tandems, Cannondale's booklet is pretty good too...
http://home.att.net/~thetandemlink/99tandsupp.pdf

If you lose this link don't fret; it's also on our Web site.