Play your song until the moment you want it to end. Press "Shift" and "Set Out" on the Tascam interface, in the row of buttons below the four cursor buttons. This will set the end point of the song you are premastering.
Press the "Menu" button, under the LCD display, and use the cursor to move right over to the "Audio CD" menu. Press "Enter" to open the menu.
Press the right cursor button until you select the "Premaster" button in the LCD menu. This will start playing your song.
Adjust the faders and panning as the song plays out to record any changes in levels. Any adjustment you make to the song as it plays out will be recorded.
Press "No/Exit," next to the cursor on the physical interface of the 2488 to exit the premaster stage once the song has finished playing. The track is now premastered and ready to burn to CD.