I am a self taught sewer, so I apologize in advance because I do not know a lot of the proper terminology for a lot of stuff. Hang in there, I'll explain things to the best of my ability and use lots of pictures.
For this purse, I used a really basic pattern (because it is fast), that you can find here. I recommend that you read through the tutorial a few times, and maybe make a bag or two without a zipper if you haven't made one like this before because I won't be going into the "how to" of making the actual bag. I'm just going to detail how to get the zipper into it. I also think this method will work with a gusseted bag with a few modifications.
Here is a picture of the finished purse so you can get an idea of how it will look when you are all done. I prefer to have my zipper about an inch down into the bag lining because that way it doesn't bubble up the way it does when you put the zipper right on top.