Originally Posted by
gyozadude
Always start with cable unattached, tension adjuster barrel screwed all the way in.... Repeat this stop screw adjustment after shifting to the lowest gear (biggest cog).
The above is good advice. If you are still having problems you can also Google
adjust rear derailleur - Sheldonbrown and Parktool results are generally the best, but you can check videos for additional information. Go through the entire procedure and also make sure cables are running smoothly.
Please either take more time initially or use Edit Post to correct spelling, typos, capitalization, etc. We put much effort into crafting a clear answer, and it helps us in doing so if your question is clear and not difficult to read.
Thank you.