Click "File," "Open." Select a Logic song project from the navigation menu. If importing an audio file not created in Logic, click "File," "New" and drag the audio file onto the new project window.
Click the "Tempo" indicator at the bottom of your project window. It reads "120" by default.
Drag the slider up or down the vertical line. Dragging up increases the tempo; dragging down decreases it.
Click "Play" to hear your changes. If you hear any distortion in your recording, or if the quality suffers, click the "Tempo" indicator again and reduce the amount of change to your tempo. Undo the change entirely by clicking "Edit, "Undo." If you adjust the tempo too much, your audio quality will suffer.