The easiest to follow derailer adjustment instructions are at the Park Tools website which can be accessed via the link already provided. Best avice: start at the beginning and do not skip any steps. Finsih at the end with a well funcitoning derailer. Take your time, be patient and watch closely what happens when you make an adjustment.
After working with electronic equipment all day, I love to come home and work on bicycles. I can see what I'm doing and get the instant gratification of knowing when I've solved a problem. Go for it.
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