The Office of Compline is the last Office of the liturgical day and one of the 'Little Hours' or Horae Minorae. Its structure differs from that of Vespers and Lauds and it has certain affinities with Prime. Both Prime and Compline historically having been monastic praxis that became imported into the secular Office.
Today is an Advent feria but Vespers are the first Vespers of St. Bibiana which is a semi-double feast. So for Compline today in the Breviary the texts are to be found at 'Feria tertia ad Completorium'.
The Office begins with Aperi Domine etc followed, not by the usual introductory rites as at the other Hours, by a request for a reader-blessing Jube, domne (or Domine in private recitation) benedicere then the blessing Noctem quietem et finem perfectum etc and Amen. After that the short lesson Fratres: Sobrii estote, et vigilate etc followed by Deo gratias and then the versicle Adjutorium nostrum and its response Qui fecit caelum. Then Pater noster is said inaudibly followed by the Confiteor, Misereatur and Indulgentiam. Then the versicle Converte nos, Deus, salutaris noster (during which a small Sign of the Cross is made on the chest) its response, Et averte and then the usual introductory rites of Deus, in adjutorium, Lesser Doxology and Alleluia.
Then comes the psalmody which since 1911 is variable (before being invariably Pss.4, 30 (vv 1-6), 90 and 133). For Tuesday's Compline this now consists of the antiphon fragment Tu, Domine followed by Psalm 11, Lesser Doxology, Psalm 12, Lesser Doxology and Psalm 15 followed by the Lesser Doxology and the antiphon Tu, Domine...custodies nos in aeternum in its entirety. The hymn Te lucis ante terminum then follows. The hymn is followed by the chapter Tu autem in nobis etc and its response Deo gratias.
Following the hymn and chapter comes the short responsory In manus tuas etc. This is followed by the versicle Custodi nos, Domine and its response Sub umbra. Then the antiphon fragment Salva nos and the NT canticle Nunc dimittis, Lesser Doxology and the antiphon Salva nos...requiescamus in pace in its entirety.
The Domincal preces are then said. Kyrie, Christe, Kyrie followed by the Pater noster and Credo and series of versicles and responses. After the last response Dominus vobiscum etc and the collect Visita, quaesumus. After that the final greeting and Benedicamus Domino, its response and the blessing Benedicat et custodiat etc. Following that the antiphon to the Blessed Virgin, Alma Redemptoris, its versicle & response and collect. Then the versicle Divinum auxillium and an inaudible Pater, Ave and Credo.
The most complex hour, Mattins, later in the week.