Does this picture below look like what you are trying to do? [ref:
Park Tool Co. » ParkTool Blog » Wheel Removal and Installation ]
Shows the nut and tab mentioned previously. As long as you have internet, search out how-to videos. (Seriously - we actually watch videos before working on our cars; makes the job sooo much easier.) You are on the right track by learning to do this yourself so stick with it if you can. There is much more than $$ - you will not be dependent on a shop, and when you do use a shop you will have a better idea if they did the work correctly.
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FB4K - Every October we wrench on donated bikes. Every December, a few thousand kids get bikes for Christmas. For many, it is their first bike, ever. Every bike, new and used, was donated, built, cleaned and repaired. Check us out on FaceBook: FB4K.
Disclaimer: 99% of what I know about cycling I learned on BF. That would make, ummm, 1% experience. And a lot of posts.