Go to expertvillage.com or youtube and search for "how to do bike repairs" there are videos that deal with adjusting the brakes and changers, and a little bit about the driveline issues.
If the bike has sat for any length of time, the chain could be binding. put it on it's smallest chainring and sprocket and look to see if any of the links are binding and not fitting the small radius.
I used to find that a lot, and a good soak in oil usually frees it up. Otherwise I've used a chain breaker a time or two to loosen up a binding chain.
Enjoy your bike,
RD