Once that the alignment is correct (when the lip of the voicing is visible through the mouthpiece, the slot stick is parallel to the top of the voicing wall, and centered in the voicing window), the mouthpiece can be attached permanently. Remove the mouthpiece one moe time (yes, I know, this is getting to be a pain) and apply slip to to all of the mouthpiece opening's surfaces. Do not put slip on to the lip.

Replace mouthpiece and re-align. This is not difficult to do this time around since all the adjustments have already been made. Apply slip on the gaps between the mouthpiece and body.

Press soft coils of clay over the slip to secure the mouthpiece to the ocarina body. With all the finger holes uncovered, blow gently (like blowing a kiss) through the mouthpiece to test the sound. You should get a clear note. If you do not, the angle of the mouthpiece may have been tipped down when pressing on the clay coils. Look down the mouthpiece to make sure the voicing lip (beveled edge) is still visible. If it isn't, tip the mouthpiece up gradually until it is.
Trim off the tips of the clay coil (Figure 1) so they are even with the end of mouthpiece. (Figure 2)

(Figure 3) With the repeated removal and re-insertion of the slot stick, the edges of the exit slot will become rough. (Figure 4)With the slot stick in, and the tip even with the end of the exit slot, use tool #7 to scrape off any rough edges. This maneuver is done frequently during the construction of an ocarina. Repeat whenever needed.

Blow through the mouthpiece to test the sound.