This step-by-step guide will explain how to do it easily
Firstly you need to have WMA MP3 Changer installed on your computer. If you doesn't have it you may download it. Choose version of your system. Download installation file and install. When it is done start WMA MP3 Changer
Now you need to add WMA file(s) which you want to convert to MP3 format. To do is press Add file button on toolbar (first button) and select WMA files to convert to MP3. Also, you may drag WMA file(s) and drop it on the program's window.
When file(s) has been added you will need to specify the MP3 format as output. Select MP3 format below the list and choose its settings. You may select from the list of predefined settings or customize your own. Customized format will be saved for further usage.
By default program stores converted MP3 files to your Music folder. You may change the output folder. To do use the lowest combo box and choose your own. Or you can set to store converted file at the same folder where source files are located.
Now everything is ready for conversion to MP3 format. To start conversion press Start button on toolbar and have a rest while conversion is in progress.
That's it. All files has been converted. To find converted file right-click on it and select Locate converted file in appeared menu. Also you may add more MP3 files and convert them to MP3 format.