The figure "tarro, dos tarros" do not have any related video at the moment.
In rueda, tarro is the most common way to change partner when in closed position. In ábaco, a quater turn left is normally corresponding to a partner change in rueda.
So the ábaco figure tarro is a quarter turn left, where you do the actual turn on beat 7.
Dos tarros in ábaco is a half turn left on 7 (two quarter turns at once).