Audacity is an excellent general purpose sound capture, editing, and sequencing program. Its user interface is straightforward, although a little quirky.
The key thing to understand with Audacity is that it works with "projects" rather than individual audio files. When you open a WAV file (say) it ends up in an untitled project containing a number of (usually one for mono, two for stereo) tracks. To save changes, you essentially export those tracks from the project.