Saving
From Audacity Manual
To return later to your unfinished work in Audacity with all tracks and edits as you left them, save an Audacity project. To play your current work in other media programs or send it to others, export an audio file such as WAV or MP3.
saves an .aup project file and a _data folder containing the actual audio. To re-open a saved project, click and open the .aup file. If you save and exit more than once, an .aup.bak backup file is created, but the .aup file should always be opened if present. When your final exported file is exactly as you want, delete the project files and _data folder to save disc space.
is for saving an empty project. It also lets you save an existing Project to a new name. This is the only safe way to rename a project. The .aup file and _data folder should not be moved or renamed manually.
To Getting Started.
