Can anyone recommend a site with instructions on doing basic adjustments like tweaking the rear derailleur? My bike is currently making a lot of noise when I switch into smaller cogs in back - when I try to go faster. It's also hesitating on certain combinations. I know you're not really supposed to use the smallest cog with the biggest crank and vice versa, but this isn't anything close to the smallest cog.

I'm probably using all the wrong terminology, but hopefully I make sense!

If this isn't something I should attempt on my own, that's good to know, too...but if it's an easy adjustment, I should know how to do it!