To make an audio recording of a Sound, go to the Action menu and select Record to disk...
In the Timeline, Multigrid, TAU editor and Wave editor, you can click the Record control at the top of the editor to go into record mode and then space bar to start the recording.
For making quick stereo recordings from the AD inputs, there is a Tape Recorder tool in the Tools menu.
There is also a module in the Prototypes called Record to Disk which you can insert anywhere in the signal flow path to record the signal at that point.
In each of these cases, you'll get a record dialog asking you for the format, resolution, and number of channels.