1.  Open the sound file by Praat (Read → Read from file... )

2.  Click on the sound file, which should display under 'Objects'. Then click 'edit' on your right. Then you will see the 

     waveform and the spectrogram of the sound.

3.  Under 'formant', select 'show formants'.

4.  Select a steady part of the vowel, click 'formant' again, and select 'formant listing'.

5.  One window will pop out with a list of formant values and the corresponding time points. Go to 'file', select 'save as',

     and save it as a text file.

6.  Open the text file with Excel. Choose 'delimited' in step 1, select 'tab' and 'space' in step 2, and then click 'finish'.