This is optional and can be turned off as described in the Measurement preparation section above.
After the measurement is performed and the level is plotted, the Save dialog box will be displayed as shown below.
Check that the file name is correct. If not, you may click the button to change the default naming. Note that after changing the defaults you need to close and reopen the Save dialog box for this to have effect. Reopen the Save dialog using File->Save As... or the button.
Click the button to save if you are satisfied with the measurement. If you are not satisfied with the result, click the button. Note that even though you save the measurement, you can remove it from the final result later.