Learn how to edit audio files using Audacity of the MAC. 1 Create an audio file by using the built in recording function in Audacity. Save the file prior to starting your editing. 2 Open the file that you created earlier and test the file by playing it. 3 You can copy, cut and paste different parts of the file by highlighting the section in your file and then right clicking (or option clicking) and choosing what you want to do from the pop up file. 4 You can also add effects by highlighting a section of the file and choose from a number of the available effects already built into the program. 5 Save and export your edited file using the main menu at the top of the screen.