Now that you've learned how to make a selection and use the zoom function, it's easy to cut out a section of a Wave file, select it, then select Edit->Cut or Control-X. The Delete key will clear the selection. Note: Be careful; if you delete it, you won't be able to paste it later.
Here's how the file looks before and after:
We suggest working with a Wave file you won't miss if you make mistakes; always save an original copy before you begin editing any audio file.