After the afternoon Minchah Prayer, the concluding meal, is eaten. The meal can be eaten at any time but must be concluded while it is still day i.e., before sunset - since one is required to "add" to the fast by beginning while it is still day. This addition to the fast has no minimum amount of time prescribed by the Torah.
It has become customary to finish this meal at least half an hour before sunset so that one has enough time for an unhurried, heartfelt recitation of the Grace after Meals, and for arriving at the synagogue in time for Kol Nidrei, which is also recited before sunset.
Although it is commendable to eat fish at the morning meal, it is customary not to do so at this meal. One should not drink intoxicating beverages, for were he to become drunk, his prayers would be an abomination. Optimally, one should eat only light foods.
After the meal is finished, Psalm 126, which precedes the Grace after Meals, is recited fervently, in the acknowledgment that we have not yet merited the final redemption.