Just click on the graph to set the current position for playback, then click the toolbar button or to set this position as start or end of the selection.Step 2: Define a selection, if needed, for the editing commands.The waveform graph and editing command buttons are then displayed.Step 1: Click to open an MP3 file for editing.To cut/edit your mp3 file, just start the program and complete the following steps: Free MP3 Cutter and Editor program is an extremely simple and handy Windows software for editing mp3 files.