Download and install Audacity (see resources) if the program is not already on your computer.
Go to the LAME MP3 encoder website (see resources).
Click the "LAME" download link to download the set-up. Save this file on your desktop.
Double-click the LAME set-up to begin running the file. You will be asked where you want to save LAME in a "Select Destination Location" box. You must remember this location the first time you use LAME.
Continue following the on-screen instructions in order to install LAME.
Open Audacity.
Click "File." Choose "Open." Search for and select the WAV you wish to convert to an MP3 file. That file will be imported into Audacity.
Click "Edit." Place your cursor over "Select" and three choices will appear. Choose "All." The entire file will be highlighted.
Click "File" once more. Select "Export as mp3." Choose a folder to hold the MP3 file and click "Save." Once you do this, a box will appear asking you to locate LAME. Click "Yes" in this box. Then, find the LAME location mentioned in Step 4. After you do so, select the LAME folder and a smaller box will appear in the middle of Audacity.
Enter the track information (such as artist and title) into the appropriate text boxes. Then, click "OK." The file will then be converted to an MP3 file.