Note that a multi-channel measurement with N channels is saved as N separate files. The exception is if saving as .wav-file, it can optionally be saved as a single file, see Measurement->Saving Defaults….
The usage should be quite intuitive. A multi-channel tag is added to the filename indicating what channel it is. Optionally a counter can be added which is useful if you are performing a series of measurements.
The maximum size of the title is 80 characters and the maximum size of each comment is 60 characters.
The defaults are set by clicking the button button (Measurement->Saving Defaults…).