Tarabi will start after the isha prayes in holy month of ramadan but it is not compulsory to complete the holy quran.
From When The Tarabi Namaz Start Where The Holly Quran Fully Complete In This Namaz?
Tarawi is a non-obligatory prayer and its purpose is to recite the whole Holy Quran during the month of Ramadan. So it is offered after Ishan Prayer and part of Holy Quran is recited every day during the month of Ramadan