You can use the Audio Editor to cut or split audio files.
To cut a region:
Open the Audio Editor by clicking the "Audio Editor" button at the bottom right corner of your screen. Click on an audio file to select it, then click on the scissors icon in the toolbar.
Drag your mouse across a region of audio and release when you've selected what you want to cut. You will see a dotted line appear where your selection ends, and you will hear a preview of your selection. If you're happy with what you hear, confirm by clicking on "Cut".