When do Holy Thursday Good Friday and Holy Friday Begin and end?

Holy Thursday begins with the Mass of the Lord's Supper in the evening of Thursday of Holy Week, which officially ends Lent and begins the Easter Triduum (the shortest season of the Liturgical year), which then runs through Good Friday and Holy Saturday up to the beginning of the Easter Vigil after dark on Saturday evening. As soon as the Easter fire is lighted, the Holy Triduum ends and Easter begins.