Joan and Linda have excellent answers. Linda is correct, that "right click" and "open with" are the keys. Make sure you check the box that says "always use this program for this extension." (I am not sure of the exact wording.)
BTW, that right click is one of those interesting places that not all computer users take advantage of. For instance, the right click is "content sensitive." That means that what you see in the right click in a word document will be different than what you see in a email document. Some issues are the same, but there is a treasure trove of items you can get to from the "right click."
Pat
If you are interested in selling your projects, you can determine your costs and profits quickly with my Spreadsheet.
If you want a lot of great information on working easier, faster and more confidently on your computer, check out my Tips and Tricks.
If you want to see my pashminas (that I successfully sell retail) check them out here. I also wholesale them.